Double Wimbledon champion Venus Williams overcame a second-set lull to beat fellow American Lindsay Davenport to reach the Wimbledon semi-finals.
Williams came through 6-2 2-6 6-1 against Davenport, who may have made her last appearance at Wimbledon.
Davenport said afterwards that a major foot operation due at the end of the season could enforce her retirement.
"It definitely ran through my mind that that could be my last singles match out there," said Davenport.
And she added that "time's running out" on her chances of winning another Grand Slam title.
Williams has looked back to something like her best at Wimbledon, but she insists she has been happy with her form all season.
"I think I've had a pretty good year - it's impossible to be in the winner's circle every time.
"Injuries have kept me off the court so I haven't been able to practise and be as confident as I normally am."
Williams got the match off to a lightning start, opening with a love service game including two aces.
I think my level of play is high enough to play well against any competitor
Venus Williams on facing Kim Clijsters in the semi-finals
She went on to break Davenport's serve at the first time of asking before rain interrupted her rhythm.
After 90 minutes off Centre Court, the 2000 and 2001 champion returned in careless mode as her compatriot broke back.
But Williams was not to be deterred and stepped up the pace, delivering some powerful forehands to break again and close out the first set 6-2.
Davenport emerged at the start of the second set in determined mood and it was her turn to deliver a string of decisive forehands.
The fifth seed easily broke Williams in the very first game and produced a high rate of first serves to hold her own games comfortably.
With the momentum clearly swinging in Davenport's favour, Williams was broken for the second time as the 27-year-old swept to the second set 6-2 to level the match at one set all.
Williams then made a decisive break to take a 3-1 lead at the start of the deciding set, and the 23-year-old was merciless as she raced through to close out 6-1.
Williams will now play Kim Clijsters in the last four.
"I expect her to play well," said Williams. "She's a very good player.
"But I think my level of play is high enough to play well against any competitor."