By Phil Harlow
BBC Sport at Wimbledon
Defending champion Venus Williams was knocked out of Wimbledon in the third round after falling to a surprise 7-6 4-6 6-4 defeat against Jelena Jankovic.
Williams' reign as Wimbledon champion is over
After taking the first set 10-8 on a tie-break, Jankovic lost her way in the second as Williams sharpened up.
But the 26th seed fought back well in the decider, and finally took the match on her fourth match point in a desperately tense last game.
Jankovic will now face Russia's Anastasia Myskina in the next round.
Williams narrowly avoided defeat in the previous round after fighting back from the brink against fellow American Lisa Raymond.
And she looked just as unsettled in this encounter as she lost the first set to her 21-year-old Serbia and Montenegro opponent after an epic tie-break.
After bouncing back in the second set, she hung on grimly in the decider, breaking Jankovic's serve when she trailed 5-3.
But Jankovic finally wrapped up victory in two hours and 27 minutes on the "graveyard" Court Two.
I was so nervous that the racquet felt like it weighed 30 lbs
There was some controversy over Jankovic's serve, with Williams complaining to the umpire that her opponent was not giving her enough time to prepare to return.
But both players played the incident down afterwards, with Jankovic insisting it had not been a deliberate ploy to unsettle Williams.
It was Jankovic's first win in three meetings with three-time champion Williams and it represents her best Grand Slam performance.
Williams admitted she only had herself to blame after losing her grip on the Wimbledon title.
"I had some opportunities, but unfortunately she played some good tennis," said a subdued Williams.
"I would have liked to have played better. I didn't get to the net enough.
"I've played her before and against someone like me she feels like she has nothing to lose - she came out and gave it her all."
Meanwhile, an ecstatic Jankovic said her surprise win was one of the highlights of her career.
"Beating the defending champion doesn't happen every day - I'm so excited," said Jankovic.
"I was so nervous towards the end of the match that the racquet felt like it weighed 30 lbs in my hand. I was shaking on match point.
"I never give up - I always fight to the end of every match."