Venus Williams rallied from a set down on Wednesday to defeat Simona Halep of Romania 4-6, 7-5, 6-3 and reach the quarterfinals of the Pan Pacific Open.
Williams, making her first appearance in the Tokyo tournament since 2009, broke serve to go up 5-3 in the second set at Ariake Colosseum and then won with a crosscourt forehand that Halep hit into the net.
"It was a very tough match," Williams said. "She played very well. I don't know how I was able to win the match. I just wanted to stay in Japan longer."
Williams, who ousted top-seeded Victoria Azarenka on Tuesday, will face Canada's Eugenie Bouchard in the quarterfinals.
Bouchard upset sixth-seeded Jelena Jankovic of Serbia 7-5, 6-2.
Making her debut in the Tokyo tournament, Bouchard broke Jankovic to go up 5-2 in the second set and then held serve to win.
Jankovic had a 5-4 lead in the first set but Bouchard won the last three games after a talk with her coach.
"I felt like I wasn't playing my best in the first set," Bouchard said. "But I stayed with her and started to get a lot more aggressive near the end of the first set and that was the turning point."
Bouchard, who is 46th in the world rankings, said winning last year's junior Wimbledon title has given her confidence to compete at a higher level.
"That gave me a lot of confidence to play in the pros," Bouchard said. "Playing week in, week out against the top players has made me a better player."
In another third-round match, fourth-seeded Caroline Wozniacki of Denmark, defeated Magdalena Rybarikova of Slovakia, 6-1, 6-1.