organisers at the French Open marked Rafa Nadal's 26th birthday by presenting him with a cake yesterday.

But the Spaniard's best present of all was watching his two biggest rivals for the title – Novak Djokovic and Roger Federer – pushed far harder than they would have expected or wished.

Both men edged through to the quarter-finals – Djokovic 4-6, 6-7, 6-3, 7-5, 6-3 against Italy's Andreas Seppi and Federer 5-7, 7-5, 6-2, 6-4 over an inspired David Goffin, a lucky loser from Belgium – and there is nothing to say they will not go on to set up a semi-final meeting. Each will insist they would rather hit top form later on in the tournament but with six-times champion Nadal looking as strong as ever, they might just be kicking themselves at having to expend so much energy in those ties.

That said, neither of them had much choice. Djokovic was all at sea against Seppi, a man he had beaten with ease seven times before. The Italian deserved his two-set lead and only the world No.1's guts and resolve got him through, after four hours, 18 minutes. He will now meet either Jo-Wilfried Tsonga or Stanislas Wawrinka. They will resume today with Tsonga leading 4-2 in the final set.

"When I was two sets down, I believed I could win the match and that's the only positive I can really pick up from today's match," Djokovic said. "I was fighting and I think because of the fight I won the match.

"I'm not worried. I'm just hoping that I can wake up tomorrow knowing that I'm in the quarter-finals. I want to forget this match today and just take the best out of it."

Federer has now reached the quarter-finals or better in a record 32 straight grand slams. To put that in perspective, only five other men have even played in each of the past 32 events. But even his usually unflappable coach Paul Annacone looked a little stressed as Federer dropped the first set to Goffin, so baby-faced he looked like he should be at school rather than on court at a grand slam event.

The Belgian admitted he had pictures of Federer on his wall as he was growing up and when the Swiss trailed 7-5, 5-5 and 0-30 on his serve, an upset looked a real possibility.

However, a couple of missed chances from the Belgian let Federer back in and although Goffin continued to play well, the third seed clinched a meeting with Juan Martin Del Potro or Tomas Berdych.

"I thought he played really well," said Federer, who will watch with interest as Del Potro looks to build on his two sets to one lead today. "He made a great impression. He took the ball early every time. If you don't hit a very good shot, he can take advantage of that.

"He's got great potential in terms of his touch and the way he reads the game. It was an interesting match."

Goffin showed a wide variety of shots and in a rare event, the two men conducted a joint on-court interview afterwards, with Federer joking that the crowd "wanted us to sort of hug each other". "And at the end, we did give each other a hug," he joked. "Like men."

After the loss of the tournament favourite, Serena Williams and the No.3 seed Agnieszka Radwanska, the women's event has now lost its top seed as world No.1 Azarenka was ousted 6-2, 7-6 by Dominika Cibulkova of Slovakia. The Belarussian had struggled to make it through to round four but was worn down by the consistency of Cibulkova, the No.15 seed.

"I don't know how to describe my performance really" Azarenka said. "I need to rest mentally, and get away from tennis a little bit."

US Open champion Sam Stosur fended off a stout challenge from American Sloane Stephens, while Svetlana Kuznetsova lost to Italy's Sara Errani and Angelique Kerber defeated Petra Martic.