Second seed Jo-Wilfried Tsonga of France had to work hard to beat qualifier Ernests Gulbis of Latvia to reach the semifinals of the Japan Open tennis tournament on Friday.

The 2008 Australian Open finalist, the highest remaining seeded player in the tournament. shrugged of a one-set deficit to score a 4-6, 6-4, 6-3 victory over the 98th-ranked Latvian.

Earlier, Mikhail Youzhny of Russia eliminated defending champion Tomas Berdych of the Czech Republic 6-2, 7-6 (8/6) to set up a semi-final meeting with 2001 champion Lleyton Hewitt of Australia.

Hewitt, seeded eighth, put an end to French qualifier Edouard Roger-Vasselin's excellent run with a 6-4, 6-0 victory.

In the last match of the day, fourth seed Gael Monfils of France defeated Beijing Olympic doubles gold medallist Stanislas Wawrinka of Switzerland 2-6, 6-3, 6-4 to earn a place againstTsonga.

Gulbis, who eliminated sixth seed Radek Stepanek of the Czech Republic on his way to the quarter-finals, hit a double fault on Tsonga's set point to tie the match at one-set all.

But he failed to secure a break opportunity in the final set, with Tsonga firing 19 aces, eight of them in the third set.

"1 tried to (maintain) focus on my game, not on his serve, because it's very difficult when he served like that. He served just unbelievably today in the first two sets," said Tsonga, ranked seventh.