Tennis-Kerber hands Serena rare loss, advances to Cincinnati semis

MASON, Ohio, Aug 17 (Reuters) - Olympic champion Serena

Williams suffered her first loss in nearly three months on

Friday as she was knocked out of the Cincinnati Open

quarter-finals, falling 6-4 6-4 to Germany's Angelique Kerber.

While older sister Venus Williams continued her progress and

moved to the semi-finals with a 6-2 6-7 6-4 win over U.S. Open

champion Samantha Stosur, Serena struggled against an impressive

Kerber en route to just her fourth defeat of the year.

Serena, who had not lost since her opening round defeat at

the French Open, complained of fatigue after her last 16 match

on Thursday but she fell on Friday to an opponent who used a mix

of intelligence and technique to make her life difficult.

Kerber, who has reached at least the quarter-finals in 12 of

17 events played this year, double-faulted on match point but on

her third chance used a blistering ace to win the match.

"I had nothing to lose today, I tried to play my best and

take it point by point because she has been playing so well

recently," said world number seven Kerber.

The German's opponent in Saturday's semi-final will be the

winner of the match between Russian Anastasia Pavlyuchenkova and

Czech Petra Kvitova later on Friday.

Venus Williams's recovery from health problems is finally

delivering some results, she reached her first semi-final since

pulling out of last year's U.S. Open with an auto-immune disease

that causes fatigue and joint soreness.

"I'd like to think that this is only the beginning for me of

more semi-finals. Of course I'm going to stay focused and try to

make it to the final as well," said Williams, who will face

either China's Li Na or top seed Agnieszka Radwanska of Poland

in the semi-finals.

"I'd like to take it a lot further. I haven't played a lot

since 2010, so this is awesome for me already."

(Editing by Frank Pingue)