LONDON (Reuters) - Serena Williams reached her ninth Wimbledon semi-final after subduing inspired former world number one Victoria Azarenka in the best women's match of the tournament so far on Tuesday.
Both players came out with music pumping through headphones and they proceeded to deliver a high-powered slugfest on the Centre Court grass as Williams hit back to win 3-6 6-2 6-3.
Belarussian Azarenka, who once spent 51 weeks on top of the rankings and who is returning to her best after a serious foot injury stalled her career, dominated the opening set, but could not sustain the tempo as Williams found another gear.
The world number one struck 46 winners, including 17 aces, as she took her record over Azarenka to 17-3 and she can now set her sights on Maria Sharapova in Thursday's semi-final -- a player she has beaten 16 times in succession.
The 33-year-old American, bidding for a sixth Wimbledon crown and 21st grand slam singles title, not to mention a fabled calendar-year grand slam after winning the Australian and French Opens, looked unstoppable by the end.
But she knew she had been in a fight against a player she respects and regards as something of a yardstick of her form.
"I feel like me and Victoria always have really wonderful matches," Williams said after her 41st grand slam quarter-final.
"She's always able to push it to three sets. We always have some great three-set matches.
"Whenever I see her name I get excited because I feel like there's going to be an opportunity to see how well I'm doing."
The answer was emphatic, even though the top seed found herself outmaneuvered in a first set in which Azarenka's tennis reached the level that brought her two Australian Open titles.
A scorching forehand earned her a break point in the fourth game and Williams netted a backhand to trail 3-1.
The 25-year-old then fired an ace to move 4-1 ahead.
A subdued Williams saved two set points at 5-2 down but was left rooted to the baseline as Azarenka pocketed the opening set with another forehand winner at 5-3.
Azarenka fought off three break points in an 18-point fourth game of the second set and Williams extricated herself from trouble with a big serve and a backhand in game five.
That proved the turning point.
Williams bellowed a roar of approval after a fizzing, dipping backhand earned her a break for 4-2 and she reeled off the next six games to take a stranglehold on the match.
Azarenka's still believed, but was helpless as Williams fired down three consecutive aces for a 5-2 lead and three more when she served for the match.
"It was really fun out there," Williams said. "I was smiling at one point and I saw Victoria smiling as well.
"It's been up and down, up and down, but somehow I'm still alive. I'm just happy to be here."
Reporting by Martyn Herman; editing by Ken Ferris