(CNN) -- Roger Federer had to come from two sets down to avoid joining top seed Rafael Nadal on the French Open sidelines as he saw off Germany's Tommy Haas 6-7 5-7 6-4 6-0 6-2 to reach the quarterfinals on Monday.
Federer shows his relief after seeing off the challenge of Haas in a five-setter.
With Nadal sensationally losing to Robin Soderling and with Novak Djokovic going out in the third round, the draw has opened up for second seed Federer as he bids to complete a set of grand slam titles.
The French Open is the only slam to evade the Swiss star, with Nadal usually barring his path, but Haas came close to spoiling the party before Federer took command.
He will now face either American sixth seed Andy Roddick or French 11th seed Gael Monfils for a place in the semifinals.
German veteran Haas led by two sets to love and had a break point in the eighth game of the third set before Federer hit back as he won 14 of the last 16 games in their clash on Philippe Chatrier.
Federer is bidding to become only the sixth man to win a career grand slam and is one shy of the all-time record of 14 grand slams by Pete Sampras.
Spain's Tommy Robredo, the 16th seed also reached the last eight with a hard-fought 6-4 5-7 7-6 6-2 win over German 29th seed Philipp Kohlschreiber.
He will face fifth seed Juan Martin del Potro of Argentina who was mightily impressive in distpatching French hope Jo-Wilfried Tsonga in their fourth round match.
Del Potro silenced the Roland Garros crowd to win 6-1 6-7 6-1 6-4 in two hours 41 minutes.