Sergio Ramos defends under-fire Cristiano Ronaldo

Sergio Ramos has leapt to the defence of under-fire Real Madrid teammate Cristiano Ronaldo.

The Portuguese struck twice in his side's Champions League last-16 second leg against Schalke 04 last week, but has struggled to hit top form in the league of late.

Ramos, however, has backed Ronaldo to play an important part in the remainder of the season.

"It's difficult being Cristiano because he's been performing at a very high level for a number of years," he told the club's official website.

"He knows himself better than anyone and he's a very competitive person, so we're not worried because we must appreciate what he brings to the team."

Ronaldo, who drew a blank in Real Madrid's 2-0 win over Levante on Sunday, has netted 41 goals in 39 games this season.