BARCELONA (REUTERS) - World No. 1 Serena Williams' 27-match unbeaten run ended with a 6-2, 6-3 defeat by Petra Kvitova in the Madrid Open semi-finals on Friday.
Czech Kvitova will face Svetlana Kuznetsova in the final after she surprisingly knocked out defending champion Maria Sharapova earlier in the day.
Williams had not lost since October but her mood appeared negative and she was slow around the court against fourth seed Kvitova, who broke the American's first service game and never looked back.
Kvitova broke serve three times in the first set and there was little resistance in the second set from a despondent Williams.
It was a setback for Williams, who won in Madrid in 2012 and 2013, and this was her first clay-court tournament of the season as she prepares for the French Open looking to win her 20th Grand Slam title.
"I have never beaten her before on court and so it is a special moment for me," Kvitova told reporters. "I am just happy to be in the final and I know it will be a tough game now against Kuznetsova, who beat me last year on clay."
Sharapova crashed out after failing to match the solid hitting of unseeded Kuznetsova who won 6-2, 6-4.
She looked tense from the start against her fellow Russian, whose consistency from the back of the court helped her break twice to win the first set.
Sharapova came to the tournament in poor form and struggled to get through her previous two matches in the Spanish capital with Caroline Garcia and Caroline Wozniacki taking her to three sets.
She failed to convert a break point at 2-1 in the second set and lost her serve in the following game. The Russian battled hard to win her next service games but went down 6-4.
"I was serving well and fighting for the points," Kuznetsova told reporters. "I am enjoying the games at the moment and just happy to be in the final."
Kuznetsova is a former Grand Slam winner at the US Open and Roland Garros but has struggled to reach those heights in recent years and is now ranked 29th in the world.