GSTAAD, Switzerland (AFP) - Top seed Stanislas Wawrinka fired down 17 aces on his way to beating Argentine eighth seed Guillermo Canas 4-6, 6-4, 7-6 (7/2) to reach the Gstaad Open semi-finals on Friday.

The home hope will face Romanian Victor Hanescu, who beat French qualifier Jeremy Chardy 6-3, 7-6 (7/3), on Saturday for a place in the final.

World number 10 Wawrinka, who now stands one victory away from a repeat of his 2005 final at this high-altitude resort, came back from a break down in the final set to force a tiebreaker.

The top seed showed his power at the right moment with two more aces on his way to clinching the two-and-a-half-hour victory.

"I was two points away from losing the match when he served for it in the third set," said Wawrinka. "But I never got worried.

"I kept fighting and hoping that his level would drop, which it did. In the tiebreak, I don't think he put in one first serve. I'm not sure if there is a top ten effect, but I'm playing with a lot of confidence. I'd rather be playing like that than not, certainly."

Wawrinka and Russian Igor Andreev, a winner over Croatian Marin Cilic, 7-6 (7/4), 6-3, are the last two seeds in contention.

Third seed Mikhail Youzhny went down to Guillermo Garcia-Lopez as the Russian lost for a fifth straight match against a Spaniard, 4-6, 7-5, 6-3.

The 1.98-metre Hanescu finally has some relief half a year after chronic back problems began to clear.

"I had back problems and was out for eight or nine months in 2006," said the one-time number 35 who reached a Roland Garros quarter-final three years ago against Roger Federer.

"But I've felt good for six months now," said the current number 80.

The 26-year-old last made an impression nearly a year ago with a final at home in Bucharest. He improved to 8-14 this season after second-round losses in Paris and Wimbledon.