There were 14 years in age, 13 years on tour, and 700-odd career matches separating Venus Williams and Eugenie Bouchard, but there was very little between them in their quarterfinal in Tokyo on Thursday. The 33-year-old and the 19-year-old stood toe to toe at the baseline, belting balls and trading leads for three sets and a little over three hours. Finally, after the momentum had swung back and forth between them half a dozen times, after they'd battled through many multiple-deuce games and taken a couple of equally long bathroom breaks, experience wore down youth and Venus ended up a 6-3, 6-7(4), 6-3 winner.

After all of these years, this will be Williams’ first semifinal appearance in Tokyo, and she has played her best tennis of the season to make it there. Despite catching dozens of service tosses, double-faulting seven times, playing a loose second-set tiebreaker, and screaming herself hoarse in frustration, Venus was good from the ground today. She controlled rallies with her forehand and found the corners with her backhand. She went after Bouchard’s short second serve often enough to break her eight times on 18 break points. And she topped it off by throwing down a 129 M.P.H. bomb that, pending official review, may have broken her own five-year-old women's record for the fastest serve in history. Even if it wasn’t a record, it was a pretty decent effort from a veteran playing her second three-set match in as many days.

Bouchard’s effort was just as impressive in defeat. She counterpunched and redirected brilliantly, and didn’t back off the baseline. She ran everything down and, meeting the ball early and on the rise, gave back as much pace as she got. Better than her game, though, was her demeanor. Bouchard never quit, never let her level dip, never let anything bother her. She got on with the business at hand, and that business almost included a third big win in what had already been a breakout week for her. With victories over Sloane Stephens and Jelena Jankovic, and a stubbornly excellent performance tonight, Bouchard may have vaulted to the head of the WTA’s Next Generation class. Only when she briefly took the lead from Venus at the start of the third set did she falter.

Venus is surging again, but it won’t get any easier for her. She’ll try to find what rest she can before she faces the winner of Svetlana Kuznetsova and Petra Kvitova in the semis.