Former world number one Venus Williams turned back the clock with some brutal hitting to overcome Canada's Eugenie Bouchard 6-3, 6-7, 6-3 Thursday and reach the semi-finals of the Pan Pacific Open.
The 33-year-old American, who won the last of her seven grand slam singles titles in 2008, recovered from a poor second set tiebreak with a series of electrifying shots and acrobatic volleys in the decider, completing victory with another ferocious forehand cross-court after a shade over three hours.
"It's hard to believe it's my first semi-final in Tokyo after all these years," said Williams, currently languishing at 63rd in the world after being diagnosed with an autoimmune disorder in 2011.
"Hopefully I can win it in a little less time. That's the goal."
Watched from the royal box by five-times Pan Pacific champion Martina Hingis, Williams showed flashes of the form that swept her to five Wimbledon titles between 2000 and 2008 as she continued her purple patch in Tokyo.
She won her last singles title -- her 44th -- at last October's Luxembourg Open.
"I've played against so many great players over a couple of generations, it seems," added Williams, who snickered when reminded Thursday was sister Serena's 32nd birthday.
"We always forget each other's birthdays. Serena's getting old, like me," smiled Venus. "She's an inspiration to me.
"I've put a lot into the game and I'm not going to give it up easily. As a professional athlete you have a window. My window's still open and I'm going to take advantage of it."
Williams upset top seed Victoria Azarenka in the second round of the $2.3 million event. But the 19-year-old Bouchard, ranked 46th in the world, pushed her hard, taking the second-set tiebreak 7-4.
"Actually I'm surprised I'm able to play these matches, I can't lie," confessed Williams after her plans for karaoke and a visit to a nail salon were scuppered by her marathon quarter-final.
"It was just determination, adrenalin and desire. These three-hour matches really cut down on my social life."
Former Wimbledon champion Petra Kvitova beat American teenager Madison Keys 6-2, 6-2 in a rain-delayed third-round match.
The Czech will return to the court later Thursday to face Svetlana Kuznetsova for a place in the last four, after the Russian saw off Romania's Sorana Cirstea 7-6, 6-1.