By Sophie Brown
BBC Sport at Wimbledon
Former champion Martina Hingis endured a miserable return to Centre Court when she let slip a final-set double-break to lose to Ai Sugiyama in round three.
Sugiyama is playing her 14th Wimbledon
The Japanese 18th seed came from behind to take the first set 7-5.
Hingis, 25, returning to the All England Club for the first time since 2001 after coming out of retirement, struck back to take the second set 6-3.
And the Swiss 12th seed led 3-0 in the decider but the 30-year-old Sugiyama battled back for a 7-5 3-6 6-4 victory.
Sugiyama, a quarter-finalist in 2004, will meet Severine Bremond of France in the fourth round.
Hingis had not dropped a set in her previous rounds here but Sugiyama, playing in her 14th consecutive Wimbledon, was tactically astute and fought hard throughout.
I played well, even in the third set. I had the momentum, I just couldn't finish it off
In sweltering conditions on Centre Court, Hingis took a bathroom break after just six minutes but it did the trick as she broke the Japanese woman on her return.
However, Sugiyama broke straight back and went 6-5 up when Hingis double-faulted on break point.
The 18th seed then calmly served out to take the set, clinching it with an ace.
Hingis broke in the second game of the second set, which was enough to level the match at one set all.
The Swiss woman, who won the Wimbledon title in 1997, continued her momentum in the decider, breaking twice to go 3-0 up.
But Sugiyama refused to give in and clawed back both breaks, Hingis finally buckling at 4-5, going wide with an approach shot to hand victory to her opponent.
It was an absorbing encounter with both players trying to move each other round the court like chess pieces and Hingis said she felt had played well despite the final-set collapse.
"It's not like I didn't feel comfortable out there," she said. "there's no explanation right now for me.
"I played well, even in the third set. I had the momentum, I just couldn't finish it off.
"Sugi doesn't really have a weakness. She's a very good player. She's really strong on the baseline and her game's more effective on this surface. She's a tough cookie."
It was the first time in six meetings that Sugiyama had beaten Hingis since they met at the 1996 Olympics in Atlanta.