Champions League: Can anybody stop Barcelona?

    Story highlights

    • Europe's top competition restarts Tuesday
    • Barcelona hot favorite to retain trophy
    • No team has done so in Champions League
    • Real Madrid, Bayern Munich also in contention

    (CNN)Barcelona hasn't lost in 30 matches, and boasts some of the world's best players in sparkling form.

    As the Champions League returns this week, can anybody stop the Spanish side from retaining its European crown?
      The knockout phase of the world's most prestigious club football competition kicks off Tuesday, with the Catalan club looking to become the first team to retain the title since the tournament was rebranded in 1992.
      If current form is anything to go by, Barcelona, which overcame Juventus in last year's final, is surely the best bet to break that record .

      Can anyone stop Barcelona?

      Barcelona's formidable forward line is the most feared in world football.
      Probably not.
      The Spanish champion has been in imperious form this season, with its front three of Lionel Messi, Neymar and Luis Suarez ripping through defenses.
      The South American trio have scored 86 goals between them, blowing away teams with wonderfully entertaining free-flowing football.
      Under coach Luis Enrique, Barca has lost just twice in the league this season -- the most recent defeat coming back in October against Sevilla.
      On Sunday it smashed six past Celta Vigo in a display which verged on the ridiculous for its sheer brilliance.
      Luis Suarez scored a hat-trick to take his tally to 39 from just 35 appearances across all competitions this season.
      The Uruguayan's third came from an outrageous penalty routine in which Messi passed the ball forward for Suarez to score -- a move previously exhibited by former Barcelona star Johan Cruyff.

      Ronaldo vs Messi ... again

      Lionel Messi and Cristiano Ronaldo could yet meet in this year's final.
      In the battle between the world's two top players, can Ronaldo end Messi's dominance and come out on top?
      Ronaldo, the all-time leading goalscorer in Champions League history with 89, has endured a frustrating season.
      The club sacked manager Rafael Benitez in early January and replaced him with the legendary Zinedine Zidane.
      Since then Real has won five out of six games and scored 23 goals in the process, but remains third in the La Liga table -- four points behind Barca.
      Ronaldo, who scored twice in Saturday's 4-2 win over Athletic Bilbao, has netted 32 times in all competitions this season -- seven more than Messi.
      But Messi has played three games fewer than the Portuguese star and could yet catch his rival.
      The diminutive Argentine has already got one over Ronaldo by winning the Ballon d'Or in January, the fifth time he has been named the world's best footballer.
      Ronaldo's Real -- seeking to extend its record of 10 European crowns -- faces Roma in the last 16, with the Italian club at home in Wednesday's first leg.

      Advantage Atletico?

      Antoine Griezmann has enjoyed a stellar season with Atletico Madrid.
      Atletico Madrid was just seconds away from winning the Champions League in 2014 before Real's dramatic late equalizer forced extra time.
      Atletico, having led for so long, was then blown away in the additional 30 minutes as Real added three goals without reply.
      This time around, Atletico -- second in the La Liga table -- will be a hot favorite to progress to the quarterfinal stage.
      Diego Simeone's team faces PSV Eindhoven in the last 16, traveling to the Netherlands for the first leg on February 24.
      France forward Antoine Griezmann has been Atletico's standout player, scoring 19 goals in all competitions.

      Dare to Zlatan?

      Zlatan Ibrahimovic will be the man to watch when PSG plays Chelsea.
      Is this the final chance for enigmatic Paris Saint-Germain striker Zlatan Ibrahimovic to win the Champions League?
      The 34-year-old, whose team is 24 points clear at the top of the French league, is out of contract at the end of this season and has yet to resolve his future.
      Ibrahimovic, whose side hosts Chelsea on Tuesday, was sent off against the English club at the same stage last season.
      The Swede was dismissed for a tackle on Oscar in the second leg -- a game which PSG managed to draw 2-2 to reach the quarterfinals on away goals.
      Zlatan Ibrahimovic: 'Guardiola is not a man'
      zlatan ibrahimovic guardiola not a man interview davies_00025226

        JUST WATCHED

        Zlatan Ibrahimovic: 'Guardiola is not a man'

      MUST WATCH

      Zlatan Ibrahimovic: 'Guardiola is not a man' 02:59
      Ibrahimovic was so incensed by the reaction of the Chelsea players to his tackle that he labeled them "babies."
      The forward, who has scored 46 goals in 118 Champions League appearances, has enjoyed another successful season in Ligue 1.
      He has scored 20 goals in 21 games and also helped his country qualify for June's European Championship finals.
      So will he be ready for the London club? Chelsea certainly won't be taking any risks.

      Goals, goals, goals

      Robert Lewandowski scored seven goals in the group stage.
      Ronaldo, Messi, Suarez, Neymar, plus Robert Lewandowski and Sergio Aguero -- if there's one thing the Champions League can guarantee, it's goals.
      Nobody has scored more than Ronaldo in this year's competition. He has 11 to his name, with Lewandowski next up on seven.
      Zenit St. Petersburg striker Artem Dzyuba has netted on six occasions, one ahead of Arsenal's Olivier Giroud and Bayern's Thomas Muller.
      While it's difficult to see past Barcelona's fantastic front three, Lewandowski could be the man to watch.
      He has 31 goals so far this season and has been one of Europe's outstanding goalscorers in recent years.
      The Poland forward, part of the Borussia Dortmund side beaten by Bayern at Wembley in the 2013 final, has scored 30 goals in his last 46 Champions League games.
      If you want to look elsewhere, then perhaps Chelsea's Diego Costa might take your fancy -- he's scored eight goals in his last 10 games.

      Will Benfica break the Guttmann curse?

      Bela Guttmann led Benfica to the European Cup in 1961 and 1962.
      Will Benfica ever win the European Cup again?
      Not unless it manages to exorcise the curse of Bela Guttmann -- the Hungarian coach who declared the Portuguese club would never again win the trophy after his departure.
      Guttmann, one of the most charismatic coaches of his generation, led Benfica to the 1961 European Cup final where it defeated Barcelona 3-2.
      With the legendary Eusebio in his team, Guttmann repeated the feat a year later by guiding Benfica to a 5-3 triumph over then five-time winner Real Madrid.
      But it all went wrong when the club refused his request for a new contract and Guttmann declared that the club would never enjoy European Cup success again.
      His prophecy rang true. Since he left, Benfica has reached five finals -- and lost every single one.
      It has also reached three other European finals -- and lost all three of those too.
      This year, Benfica has made it through the group stage and faces Zenit in the last 16, with the first leg in Lisbon on Tuesday.
      The Russian club, which has a Portuguese coach in Andre Villas-Boas, has won five out of six Champions League games this season and finished top of its group.

      Can Gent write new chapter in fairytale?

      Danijel Milicevic is Gent's top scorer in the competition with three goals.
      It's the story of the competition so far -- how Gent became the first Belgian club to reach the last 16 of the Champions League.
      Such an achievement is even more remarkable given the club had €23 million ($25.6 million) of debt when president Ivan de Witte took over in 1999.
      Now, with the finances in good shape and a budget of around $28.5 million, it is competing against the biggest teams in Europe after winning its first Belgian league title last season.
      Gent won its final three group games to progress to the knockout phase, finishing second behind Zenit.
      After taking just one point from the opening three games, Gent defeated Valencia before also picking up victories against Lyon and Zenit.
      It now faces German side Wolfsburg -- another team making its debut in the knockout rounds -- with the first leg in Ghent on Wednesday.

      One giant will fall

      Bayern's Arturo Vidal will face his former club Juventus.
      It's a titanic clash between two of the most famous names in world football -- so which will come out on top when Juventus faces Bayern Munich?
      The two teams last met in this competition in 2013, with the German side prevailing 4-0 on aggregate on its way to winning the title.
      Bayern, a five-time European champion, will start as favorite after enjoying another successful season under Pep Guardiola.
      The Spanish coach, who will depart at the end of this season to join English club Manchester City, has suffered two semifinal exits since taking charge.
      Bayern was beaten last season by his former club Barcelona, losing the first leg 3-0 at Camp Nou.
      Italian champion Juventus has reclaimed top spot in Serie A, having won 13 consecutive games in all competitions. It hosts the first leg on February 23 in Turin, where it is unbeaten since August.
      Bayern, eight points clear in the Bundesliga, has lost just twice this season, including a 2-0 defeat at Arsenal in the group stage -- which it gained revenge for three weeks later with a 5-1 win.

      England expects?

      Manchester City goakeeper Joe Hart has been in fine form.
      The Premier League claims to be the best in the world, but this season has been tough for the English teams.
      Manchester United, a club with such a rich European pedigree, didn't make it through the group stage after enduring a miserable return to the competition.
      Arsenal, which lost its first two games of the group stage, somehow managed to make it through after pulling off a remarkable comeback.
      It faces Barcelona -- the team which knocked it out of the competition last season -- with the first leg in London on February 23.
      But Arsenal has one advantage this time -- its former Chelsea goalkeeper Petr Cech has never conceded to Messi in six meetings.
      Man City 'dealing' with Pep speculation
      joe hart pep guardiola manuel pellegrini manchester city intv_00024824

        JUST WATCHED

        Man City 'dealing' with Pep speculation

      MUST WATCH

      Man City 'dealing' with Pep speculation 03:37
      "It's great," Cech told the competition's official website.
      "Not many can say they've played against Messi and he hasn't found a way to get past. But if he scores and we progress then it's not really important.
      "If he scores a hat-trick and we go through then I won't mind."
      Chelsea is enjoying something of a renaissance under interim manager Guus Hiddink, who replaced Jose Mourinho in December.
      The Dutchman, in his second spell at Stamford Bridge, has helped the 2012 champion steadily climb up the Premier League table -- but star-studded PSG will be at another level from the sides the Blues have faced recently.
      Manchester City's season is in danger of imploding after two damaging defeats in the English title race.
      City, which finished top of its Champions League group ahead of Juve, travels to Dynamo Kiev on February 24.
      Manuel Pellegrini's team will need to improve after losing at home to title rivals Leicester City and Tottenham in its last two games.

      Have your say

      Who's your pick to win the Champions League?
      Will Barcelona repeat its heroics of last season? Can Ronaldo inspire Real? Will Bayern blow the rest away?
      Get in touch with us on our Facebook page and on Twitter to let us know your thoughts.
      And make sure you stay tuned to our coverage @CNNFC and @CNNSport.