Los Angeles  - Third seed Dmitry Tursunov was forced out in his opening match Wednesday at the Los Angeles Open by a left ankle injury, giving a 6-4, 0-1 second-round win to Australian qualifier Carsten Ball.

California-based Russian Tursunov, 2006 losing finalist to German Tommy Haas at UCLA, was unable to continue as number 205 Ball, son of a former Aussie tennis player, made his only appreciable showing of the season at the ATP level by reaching the quarter-finals.

The outsider, making his third career ATP start after the 2008 US Open and the Australian Open in January, is to play next against John Isner.

The unseeded US big hitter, his ranking a career-best 77th, got lucky as he overcame four missed match points and the effects of a tumble in the heat of a tiebreaker, which looked to have turned his ankle, before eliminating Baghdatis 6-3, 7-6 (13-11).

Isner, who played the semi-finals last weekend in Indianapolis, Indiana, after making a return to the game following glandular fever, was seen by the trainer when he crashed to the cement, favouring his ankle.

After treatment, he was able to walk to the sidelines and resume the match, which he won a few moments later.

Isner struck 11 aces to squeeze into his fourth quarter-final of the season.

In other matches, top seed Haas begins the search for his third LA trophy with an opener against US player Jesse Levine, while eighth seed Marat Safin was bidding for the last eight against Ernests Gulbis of Latvia. (dpa)