- Real Madrid to play Manchester United in the last 16 of the European Champions League
- The tie will be the first time Cristiano Ronaldo has returned to United since leaving in 2009
- Barcelona drawn with AC Milan in another clash of past European champions
- Celtic face Juventus while Bayern Munich play Arsenal
Thursday's draw for the last 16 of the European Champions League threw up a series of mouthwatering ties between a number of the continent's top teams -- including a clash between past winners Real Madrid and Manchester United.
The pairing, which means Cristiano Ronaldo will return to Old Trafford for the first time since leaving United for the Spanish side in 2009, headlined a triol of standout ties after the draw was made at headquarters of European football's governing body UEFA in the Swiss city Nyon.
"Oh yes, Madrid!! What a great couple a games that'll be!! @Cristiano see u soon bro!!," tweeted United's former England captain Rio Ferdinand.
Another Spanish club, four-time champions Barcelona, have been pitched into another heavyweight battle as they take on Italy's AC Milan, whose seven European crowns are second only to the nine boasted by Real.
"We will play against Milan! It will be a great qualifying round!" tweeted Barcelona midfielder Cesc Fabregas.
The draw came on the same day that Barca coach Tito Vilanova was due to have surgery to remove a cancerous tumor.
Elsewhere, beaten 2012 finalists Bayern Munich will take on United's English Premier League rivals Arsenal -- whose striker Lukas Podolski will return to the German club where he struggled to make an impact between 2006 and 2009.
"I think we enter this match as the slight favorites, but we can be making the mistake of underestimating them," Bayern chairman Karl Heinz Rummenigge told UEFA's official website.
"Arsenal have struggled at times in the league over the last few months, which a look upon the standings in the Premier League will tell you. But by no means will this be an easy game for us."
Many experts, including former Manchester United goalkeeper Peter Schmeichel, are tipping Borussia Dortmund for glory this season and the Germans must beat Ukraine's Shakhtar Donetsk if they are to repeat their 1997 success.
Scottish side Celtic, in the last 16 of the competition for only the third time, have been rewarded with a draw against Italian champions Juventus -- whose last European crown came back in 1996.
In the three remaining ties, Galatasaray of Turkey take on the third German team into the knockout stage, Schalke, while 2004 champions Porto have been drawn against Champions League debutants Malaga and Spanish side Valencia will play big-spending French club Paris Saint-Germain
The first legs will be played between February 12-13 and 19-20, with the return legs taking place between March 5-6 and 12-13.
Of the teams who dropped down to the Europa League after failing to progress from the group stage, European champions Chelsea will play Czech side Sparta Prague in the last 32 of the second-tier competition.
Romania's Cluj take on 2010 Champions League winners Inter Milan, Russia's Zenit Saint-Petersburg will play Liverpool and Portugal's Benfica will face Germany's Bayer Leverkusen.
BATE Borisov of Belarus came out of the hat with Turkey's Fenerbahce, Greek side Olympiakos got Spain's Levante and Ukraine's Dynamo Kiev will play French team Bordeaux.
Dutch side Ajax face fellow former European champions Steaua Bucarest of Romania.
In other key ties, Spain's defending champions Atletico Madrid will play Russia's Rubin Kazan, English side Tottenham take on French team Lyon, while Italy's Lazio and Napoli are up against Germany's Borussia Monchengladbach and Czech club Plzen respectively.
These matches will be played on February 14 and 21, while the last-16 ties are on March 7 and 14.