GSTAAD, Switzerland -- Wimbledon champion Roger Federer won his 15th straight match Saturday, beating Gaston Gaudio 6-1, 7-6 (6) in the Swiss Open semifinals.

Federer's opponent in the final will be Jiri Novak, who eliminated his doubles partner, Radek Stepanek, 7-5, 6-1.

Federer needed three match points to get past the fourth-seeded Gaudio. Leading 6-4 in the tiebreaker, Federer lost his first chance to win the match on a contentious point -- a wide shot the line judge didn't see because Federer blocked his view.

The chair umpire refused to climb down and check the mark on the clay, saying that Federer continued to play the point. Unyielding, Federer called for the tournament referee, who agreed with the chair umpire.

Federer lost the next point, too, but then claimed two straight, ending the match when Gaudio put a return in the net.

Federer already owns a tour-leading five titles in 2003.

He has won four of seven career matches against Novak, including the last three.

Novak won this clay-court tournament in 2001.