Serena Williams survived by far the biggest first-week test of her Wimbledon campaign as she came from a set down to see off the gutsy challenge of 25th seed Jie Zheng.
Williams previously held a 5-0 win-loss record over Zheng, but looked ordinary at times on the Centre Court where she has previously won four Wimbledon titles.
Zheng often matched Williams for skill and athleticism, but the American's powerful serving - she registered a remarkable 23 aces - enabled her to record a 6-7 (7/5) 6-2 9-7 win.
Defending champion Petra Kvitova sailed into the second week of Wimbledon courtesy of her most accomplished performance of the tournament so far.
The fourth seed dropped just one game on her way to a 6-1 6-0 win over Uzbekistan-born American Varvara Lepchenko, setting up a fourth-round meeting with Francesca Schiavone in the process.
That match will no doubt present a harder task for the Czech, but for now she can reflect on a hassle-free opening week that has seen her lose just 13 games in total.
She appears to have got stronger as she has gone along too, having conceded eight games to first-round opponent Akgul Amanmuradova and four to Great Britain's Elena Baltacha last time out.
The only time she looked in any trouble today was when she conceded two first-set break points, but she saved them with ease.
She won 53 points to her 53rd-ranked opponent's 28 and now has a day to prepare for her meeting with Italian Schiavone, who secured her passage through with a similarly routine 6-0 6-4 win over Klara Zakopalova.