Losses must be effecting Nadal: Federer

Roger Federer believes that Rafael Nadal is still the favourite to win a sixth French Open title, but says it will be interesting to see how he copes mentally with his recent losses to Novak Djokovic.

The Spanish world number one has lost his last four matches against the Serb - all coming in Masters Series finals in Indian Wells, Miami and more recently on the claycourts of Madrid and Rome.

Those wins have allowed Djokovic to compile an incredible 37-match winning streak for the year that has taken everyone by surprise including Nadal.

The Spaniard has only lost once at Roland Garros since his debut in 2005 - to Robin Soderling in the 2009 fourth round - but Federer believes that he could have some doubts in the back of his mind heading into this year's tournament.

"It is going to be interesting to see how Rafa deals with the situation mentally. When all is said and done he has lost his last four straight Masters 1000 events to Djokovic," he told L'Equipe sports daily.

"That must have some effect on him. Maybe he lost in Rome because of what happened in the three previous finals ?

"I am not going to worry about him, but there is no doubt that he is facing an important point in his career. Mentally it can't be that easy for him.

"For myself I don't think it is the same as regards Djokovic.

"Even if I have lost my last three games against him I don't think he was dominating me.

"In Rafa against Novak that could count - worth keeping an eye on it."

On his own prospects Federer said he felt relaxed and confident, having lifted all the strain of his shoulders by finally winning at Roland Garros in 2009 to complete his career Grand Slam set.

And coming in slightly under the radar of Nadal and Djokovic suits him just fine, he said.

"There is for sure less pressure on me than in the previous years," he said.

"Last year I was the defending champion, the previous years every one was asking why I had never won this tournament.

"This year I have a lot less demands on my time - media, promos, sponsors etc.

"It's much more relaxed. I have never had such a calm week before the start of Roland Garros."