Rock-solid Serena downs champion Kvitova

American Serena Williams celebrates her women\'s singles quarter-final victory Four-time Wimbledon winner Serena Williams reached the semi-finals at the All England Club on Tuesday with a 6-3, 7-5 defeat of defending champion Petra Kvitova. The US sixth seed brought all her experience to bear as she punished the Czech title-holder for missing a chance to take the second set.
The 30-year-old came through her quarter-final in an hour and 24 minutes under the Centre Court roof.
She faces either Australian Open champion Victoria Azarenka, the Belarusian second seed, or in-form unseeded Austrian Tamira Paszek in the semis.
\"She\'s been playing so well on grass, hasn\'t lost since last year, so that was tough,\" Williams said of Kvitova.
\"I have absolutely nothing to lose so it\'s really fun. I\'m having the time of my life out here and enjoying every moment. It\'s exciting.
However, Serena knows she will have to step up another gear in the semi-finals.
\"I\'m going to have to if I want to win the title. There\'s a lot of people vying for it still,\" she added.
She said a fifth Wimbledon singles title was \"definitely something that I\'ve thought about.\"
It is only the second time she has reached a Grand Slam semi-final since winning the 2010 Wimbledon title.
Williams had won her previous two encounters with Kvitova, both in 2010, knocking the 22-year-old left-hander out of the Australian Open second round and the Wimbledon semi-finals.
The pair were the only two champions left in the draw after the first round exit of Serena\'s sister Venus, and world number one Maria Sharapova in the last 16.
Williams fired 23 aces -- a Wimbledon women\'s singles record -- to make it into the last 16 and was raining down booming serves against Kvitova, winning 86 percent of points on her first serve.
Serena dominated the first set and required just the one break, secured when the Czech fired long to make it 4-2.
Williams had her first set point when Kvitova made another mistake, hitting the net. However, the champion recovered to take the game on a deuce.
The American had her second set point when Kvitova hit the net again and took it when the Czech overhit.
With Williams giving her no margin for error, Kvitova seemed in a more determined mood in the closely-fought second set.
Kvitova won a tough battle for the seventh game and the Czech secured her first break point of the match to make it set point when 5-4 ahead.
But she could only put her next return into the net and Williams showed her ruthless side on the following point, blasting the ball at Kvitova from close-range.
The Czech returned the shot but Williams finished it off to stay in the set.
Williams then did what veteran champions do and punished Kvitova for missing her chance.
She earned herself a break point next game and went 6-5 ahead when Kvitova hit a forehand into the net.
Williams then served three aces for match point and won it when Kvitova could not return her next serve.