PARIS, June 4 (Reuters) - Serena Williams proved she is fallible after all with a mid-match implosion against Svetlana Kuznetsova at the French Open on Tuesday but again underlined her rapacious appetite for grand slam silverware to set up a semi-final against Sara Errani.
A 6-1 3-6 6-3 scoreline in the 31-year-old's favour disguised a fitful performance from the American who started like a runaway express train, came to a grinding halt in the face of a fierce Russian revival, then, re-stoked the fire to charge to victory.
The win for the 2002 champion took her current sequence of victories to 29 and few would bet against her extending that to 30 against last year's runner-up Errani who got the better of fourth seed Agnieszka Radwanska.
Despite being ranked fifth in the world, Italian Errani had never beaten a top-four player before and wavered when serving for the match at 5-4 in the second set, surrendering her serve to love. However, she recovered to win 6-4 7-6(6).
Two middle-aged gentlemen sat on a bench inside the grounds just before the start of play, both holding cards asking to swap their centre court tickets for places on Suzanne Lenglen.
The reason being Williams was about to take to a sun-bathed Lenglen arena and, with all due respect to Errani and Radwanska, watching the American at the business end of a grand slam tournament is a sight not to be missed.
They may have been wanting to swap them back later, however, as Roger Federer, arguably the greatest spectacle in sport, was set to take on home favourite Jo-Wilfried Tsonga in one of two men's quarter-finals taking place.
The winner of that one will take on either fourth seed David Ferrer or fellow Spaniard Tommy Robredo, the iron man of the tournament after three consecutive victories from two sets down.
Williams and Kuznetsova, the most eye-catching of the women's quarter-finals, did not disappoint.
It all started in messy fashion with Williams needing treatment on her finger even before a ball had been struck in anger. She then double-faulted twice in her opening service game which she eventually held after saving a break point.
After her sluggish start, 15-times grand slam champion Williams turned on the after-burners to leave Kuznetsova, a former French Open winner, sucking up exhaust fumes.
Kuznetsova, wearing a tie-dye outfit, disappeared off court for some treatment and returned a few minutes later transformed.
Williams had not dropped a service game in the entire tournament until Tuesday but twice Kuznetsova pounced to muffle the greatest delivery in women's tennis to march 4-0 ahead.
The American clawed back a break and had three break points to get back to 4-5 but Kuznetsova managed to level the match.
Kuznetsova broke Williams to lead 2-0 in the decider and the match was turning into a horror show for the world number one as she faced three break points in the next game.
That was when the old survival instincts kicked in. Somehow she wriggled out of trouble and held to trail 1-2 before picking Kuznetsova's pocket in the next game to make it 2-2.
A huge roar and a pump of her fist signalled Serena was back in the groove and although she had to fend off a break point in the next game she romped away to victory.
Errani, relishing the Parisian clay as she did last year, managed the difficult feat of out-manoeuvring Radwanska in a match littered with service breaks.
The diminutive Italian, playing her 81st match on the WTA Tour this year, including doubles at which she excels, wrapped up victory on her second match point.
She will have plenty of advice for her forthcoming clash with Williams as doubles partner Roberta Vinci, whom she was in action with later, lost to the American in round four. (Reporting by Martyn Herman; Editing Sonia Oxley)