PARIS - Decoding Rafael Nadal's self-evaluations can be a tricky proposition.

Listen, for example, to the way the top-seeded Nadal spoke about his game and his mindset after handling 37th-ranked Ivan Ljubicic of Croatia 7-5, 6-3, 6-3 Monday to reach the quarterfinals at the French Open, improve his record there to 42-1 and get closer to tying Bjorn Borg's record of six championships in Paris.

Nadal chastised himself for being "too anxious." He said he needs to "hit the ball with a little bit more conviction." Looking at the big picture, Nadal insisted: "The thing is, you have to be (a) realist, and today, I'm not playing well enough to win this tournament."

Maybe he's playing possum. Maybe he's being sincere. Or maybe - as explained by Toni Nadal, Rafael's uncle and coach - this is just the way his nephew is.

In the next round Nadal will face No. 5 Robin Soderling of Sweden, the only man to defeat Nadal at the French Open - in the fourth round in 2009. It's also a rematch of last year's final, which Nadal won in straight sets.

34th-ranked Juan Ignacio Chela of Argentina put in a lot of work before edging Alejandro Falla of Colombia 4-6, 6-2, 1-6, 7-6 (5), 6-2 to return to the Roland Garros quarterfinals for the first time since 2004. Chela will play No. 4 Andy Murray or No. 15 Viktor Troicki, whose match was suspended because of darkness tied at two sets each.

Maria Sharapova made it back to the quarters by erasing deficits in both sets and beating 12th-seeded Agnieszka Radwanska of Poland 7-6 (4), 7-5. The three-time major champion fell behind 4-1 in the first set, then 5-3 in the second, where she had to fend off five set points.

Sharapova finished with far more winners, 47-13, and unforced errors, 44-12. Her quarterfinal opponent will be No. 15 Andrea Petkovic of Germany, who defeated No. 25 Maria Kirilenko 6-2, 2-6, 6-4. Another quarterfinal will have No. 4 Victoria Azarenka of Belarus against No. 6 Li Na of China.

The No. 2-seeded Novak Djokovic's quarterfinal opponent, Fabio Fognini of Italy, pulled out of the tournament Monday because he hurt a left leg muscle during his five-set win a day earlier.

That won't count as a victory for Djokovic, so his winning streak stays at 43 matches overall - he's 41-0 in 2011 - heading into what could be a semifinal against 16-time Grand Slam champion Roger Federer.