(CNN) -- As Lionel Messi set yet another record, scoring in his 19th successive league match for Barcelona, Jose Mourinho was left reflecting on the reasons why his Real Madrid team have been also-rans in La Liga this season.
"We are not scoring many goals, that is the truth. Perhaps one of the differences compared to last season," Mourinho told reporters after Saturday's 1-1 draw with Zaragoza left his side 13 points behind Barca.
"In four chances we'd score three; in six, four, etc. We scored goals with great ease and the only player that has kept a similar average is Cristiano, all the others have dropped in terms of the number of goals scored and obviously the team suffers because of that."
Cristiano Ronaldo has netted 28 of Real's 72 goals from 29 Spanish league games -- the second highest behind Barca's 90, of which 43 have come from Messi including 29 in this 19-match streak.
Last season Real posted a record 121 from 38 matches, earning an unprecedented 100 points on the way to winning the title, but like Barcelona suffered heartbreak in European football's biggest competition with a semifinal exit in the Champions League.
Mourinho said Real's realistic goals for this season are now the Spanish Cup and an attempt to win the club's first European title since 2002, and 10th overall.
His players have scored 18 times in eight games in the tournament this season, edging past Manchester United in the last 16.
"The goals will come. If they don't come on Wednesday we hope that they come in the next match," he said ahead of the first leg of the quarterfinal clash with Turkish club Galatasaray in Madrid.
Mourinho said that goalkeeper Iker Casillas was unlikely to be in the squad despite Spain's World Cup-winning captain having recovered from injury.
"I don't think he'll be there on Wednesday. One more week. I think he'll be in the squad for the match against Levante," Mourinho said.
"I can never say that a player is going to be in the starting XI from now until the end of the season. Diego Lopez has played an important role, he has helped the team because he has saved goals.
"And playing as he has been since joining our side, in difficult matches such as that against Manchester or Barcelona, in football we have to be honest with ourselves and our players, and following that line, it is very hard to take him out of goal."
Barcelona will be boosted for Tuesday's Champions League trip to Paris Saint-Germain by the return to fitness of key midfielder Xavi and attacking fullback Jordi Alba.
Both trained alongside coach Tito Vilanova, who ran just his second session since returning from cancer treatment in New York.
Vilanova missed Saturday's 2-2 draw with Celta Vigo, in which Messi became the first player to score against every team in the league in successive matches.
Eric Abidal, who was named in the squad against Celta for the first time since his liver transplant, is also traveling to France on Monday.
Meanwhile, Real stayed second in La Liga after city rival Atletico drew 1-1 with Valencia on Sunday.
Visiting Valencia took the lead in the first half through Jonas, but Atletico's top scorer Radamel Falcao immediately replied with his 22nd in La Liga this season from Arda Turan's cross.
Fourth-placed Real Sociedad also drew, 2-2 at Espanyol -- whose defender Javi Lopez conceded an own-goal for the equalizer with 14 minutes left.