Cristiano Ronaldo was left frustrated again by Lionel Messi in Madrid on Wednesday.

The Portuguese criticized his team's tactics after its 0-2 Champions League defeat to Barcelona.

"I don't like it, but I have to adapt because that's the way it is," the world's most expensive player said.

While Ronaldo struggled, World Player of the Year Messi rose to the occasion, scoring twice. The 23-year-old Argentine took his season's tally to 52 in all competitions, including an unrivalled 11 in the Champions League, with a clever near-post flick and a mesmerizing second that left Real defenders trailing in his wake.

It had 71 percent of possession while Real sat back rather than press higher up the pitch and Ronaldo could be seen angrily gesticulating at his teammates as he urged them forward.

"It's much easier against 10. I wish I could get the chance to play against 10 like he did," Ronaldo said referring to Messi's performance.

"At 2-0 down and away from home ... anything can happen in football, but we know it will be very difficult," he said of the side's chances of making the final in London on May 28.

Barca's players were cautious about the second leg and brushed off Real's complaints over the refereeing.

"This time justice has been done and I think football has won," Spain midfielder Xavi told reporters.

"Their play is speculative and they have no other recourse except to play dirty, as their coach (Jose Mourinho) has instilled in them. We have never sacrificed our style."

Barca defender Gerard Pique added: "The sending-off wasn't the key, because for the first 60 minutes Real didn't try to play football either. When you play to the limits of violence, sometimes you get burned."