If the definition of a champion is someone who finds a way to win when not at their best, look out for Serena Williams.
Forty-eight hours after a Wimbledon women's record of 23 aces got her out of trouble against Jie Zheng, Williams gave another error-strewn performance in beating Yaroslava Shvedova 6-1, 2-6, 7-5.
"I just felt like today I was sluggish out there, just pulling myself together mentally," Williams said. "But I feel I can do a lot better, which is comforting. If this is my best, I'm in trouble."
The former Wimbledon champion will surely need to improve in her quarter-final against Petra Kvitova, the defending champion, although she has the consolation that today's match will be played on Centre Court. Yesterday, Williams was sent to Court Two, the furthest of the show courts from the locker rooms, and there were chaotic scenes as spectators mobbed her when she left the stadium.
"I was totally mobbed," she said. "I literally was almost knocked over today. The security was tons of security guards in there just going nuts and screaming. I've never heard them scream so loud."
Shvedova, the world No 65 and a wild card here, was always likely to be dangerous. On Saturday, the 24-year-old from Kazakhstan became the first woman in the Open era to win a "golden set", winning the first 24 points of her match against Sara Errani.
Shvedova struggled to find any rhythm, however, and she was 0-5 down after 20 minutes and lost the first set six minutes later. There were signs of a recovery at the start of the second, and at 3-2 Shvedova broke serve. When Williams served at 2-5, superb defence followed by a backhand pass down the line set up set point, which Williams saved; on a second the American put a forehand in the net. Williams took out her frustration on her racket, for which she was given a code violation.
The third set was tight, but Shvedova had greater difficulty holding on to her serve. She saved a break point at 3-3 and went 0-40 down at 4-4. With light rain starting to fall, Shvedova was forced to play without her glasses. She served two double faults in succession at 5-5, 15-15 and put a backhand wide on break point. Williams then completed the job with some panache.
Williams, who finished the match with a rasping backhand, said she had to pick up her game following her defeat by Virginie Razzano, the world No 111, in the French Open, her first defeat in the first round of a Grand Slam.
"I need to get over that," she said. "I was really upset."
Asked about her confidence, Williams replied: "Well, I'm Serena Williams. I'm very confident."
Kvitova also struggled yesterday, before beating Francesca Schiavone 4-6, 7-5, 6-1. The match turned towards the end of the second set, when the rain began to fall. Schiavone complained but, despite two short breaks, was told to play on.
"When it's humid, the grass, you can't play," Schiavone said later.
Less than 24 hours after their national football team lost in the final of the European Championship, the two other remaining Italians in singles competition also went out. Roberta Vinci was beaten 6-2, 6-2 by Austria's Tamira Paszek and Camila Giorgi went down 6-2, 6-3 to Agnieszka Radwanska.