Roger Federer of Switzerland rallied in two tiebreakers to beat Robin Soderling of Sweden 7-6 (5), 7-6 (8) and advance to the quarter-finals of the Madrid Masters on Thursday.
Neither player dropped serve in the match, sealed when the top-ranked Federer correctly challenged that the final two points were hit out by Soderling.
Each player receives two challenges a set in this tournament. If he is correct with a challenge, the player retains the same number of challenges. If the player is incorrect, one of the challenges is lost.
Federer, who served 13 aces, trailed 5-2 in the first-set tiebreaker and 4-2 in the following one.
``I served a lot of good first balls,'' said Federer, who will next play American Robby Ginepri after he topped seventh-seeded Tommy Robredo of Spain 6-3, 7-6 (3).
Fourth-seeded David Nalbandian of Argentina defeated wild-card Tim Henman of Britain 6-2, 2-6, 7-5 and will now face Russia's Marat Safin in a repeat of the 2004 final. Safin rolled past Kristof Vliegen of Belgium 6-3, 6-2.
Earlier, Tomas Berdych served 23 aces to beat sixth-seeded American Andy Roddick 7-6 (7), 6-3.
The 11th-ranked Czech had the only break of the match in the sixth game of the second set, hitting a winner after Roddick had received treatment on his left ankle.
``It's the same ankle I had injured earlier this year during the clay-court season. I just kind of tweaked it again,'' Roddick said.
Roddick doesn't think the injury will keep him out of the Oct. 28-Nov. 6 Paris Masters as he looks to clinch his spot in the Masters Cup.
``I'm in pretty good shape right now _ I think I'm closed to being confirmed,'' Roddick said. ``But the priority now is to get healthy because I'm not sure what the upside to playing in Shanghai on a bum ankle is.''
Berdych will play the winner of the Rafael Nadal-Tommy Haas match scheduled for later Thursday.
Fernando Gonzalez of Chile, seeded 10th, advanced after Joachim Johansson of Sweden withdrew with a throat infection.
© The Canadian Press, 2007
