Roger Federer will begin Monday's fourth-round French Open match against Tommy Haas still getting used to the idea that he is now the favourite to win his first ever French Open title after Rafael Nadal's shock exit at the hands of Robin Soderling.

After 31 consecutive victories at Roland Garros the defending champion Rafael Nadal of Spain lost in 4 sets to the Swede Robin Soderling in a huge upset.

The shape of the draw has changed dramatically with Nadal and Novak Djokovic out of the picture, presenting Federer with his best chance to finally pick up the one and only grand slam title to have eluded him.

With the Serb no.4 Novak Djokovic also out, Federer is the top remaining seed along with Britain's Andy Murray.

"I believe Federer, as the tournament turns out today, is the favourite, and he has a good opportunity to win this tournament," beaten Spanish eighth seed Fernando Verdasco said.

It's potentially the Swiss No.2's last real chance to finally pick up the only grand slam title to have eluded him, and to equal Pete Sampras's unbeaten record of 14 major titles.

Roger Federer faces Tommy Haas, ranked 63rd in the French Open fourth round.

Federer, seeking a record-equalling 14th grand slam title, has an 8-2 winning record against the 31-year-old Tommy Haas, who is aiming to reach his first Paris quarter-final.