London: Four-time champion Serena Williams held off a gutsy challenge from China's Zheng Jie for a 6-7 (7/5), 6-2, 9-7 win on Centre Court to propel her into the fourth round at Wimbledon.
The Chinese 25th seed provided the American with a serious examination over nearly two and a half hours but Williams showed she has lost none of her gritty determination as she finally made the breakthrough in the third set.
"It was good to win that. I needed a tough match like that and she's always playing me incredibly well," said the sixth seed.
"We always have unbelievable matches together. I thought I definitely want to go out with a bang.
"I'm just fighting everything and playing hard. She's playing unbelievable on grass so I'm just doing the best I can."
Williams faces Yaroslava Shvedova of Kazakhstan for a place in the quarter-finals after the wildcard knocked out 10th seed Sara Errani of Italy, the French Open runner-up, 6-0, 6-4, taking every point in the first set.
Zheng hadn't been past the Wimbledon second round since becoming the first wildcard to reach the semi-finals at the All England Club four years ago.
The 28-year-old, who was beaten by Williams on that occasion, was making only her second appearance in the last 32 of a Grand Slam since 2010.
Williams opened the serving and comfortably took the first game to love but Zheng responded in kind, showing she was prepared to match her trophy-laden opponent.
The Chinese was 40-0 up in the sixth game when, with the sun in her eyes, she served into her own half of the court, the ball bouncing over the net like a ping-pong serve. But she recovered to take the game.
Both players were holding serve in style, with just five points conceded in the first eight games.
Zheng was left serving to stay in the set at 6-5 down and was pegged back to deuce. However, she won the game with an aggressive charge to the net.
In the tie-break, Zheng got 5-2 up but Williams levelled matters. The American then hit the net to give Zheng set point and then shot wide to concede the set.
Williams dominated the second set, which went with serve until she broke in the fifth game, taking it when Zheng hit the net.
Stepping it up a gear, Williams won the next game to love and then broke to love and served for the set without conceding.
The Chinese had three break points in the fourth game of a pulsating final set but some Williams aces and Zheng errors took it to 2-2.
Once it got to 5-6 and beyond, the pressure was always on Williams to hold her serve.
Williams had a break point on a deuce at 7-7 when Zheng shot long and then won the game when the Chinese sent a shot ballooning skywards.
Serving for the match, the American was not found wanting. Zheng held off the first match point with an excellent return of serve and survived the second when Williams overhit.
But the Chinese could hold out no more, leaving Williams looking somewhat relieved.