Defending champion Serena Williams will meet Russian teenager Maria Sharapova in the women's singles final after thrilling victories on Thursday.

Serena came from a set down to beat Amelie Mauresmo in a classic after Sharapova had done likewise to down former champion Lindsay Davenport.

Williams lost the first set and was a break down in the second before staging a memorable fightback to record a 6-7 (4/7) 7-5 6-4 victory.

Mauresmo looked on the verge of a shock win when she led 3-1 in the second set and saw her frustrated opponent smash her racket into the turf.

But the French fourth seed then needed treatment on a back injury and eventually lost the second set, Williams finally sealing the win on her first match point after two hours and 27 minutes.

Williams, aiming to become the first woman to win three consecutive titles since Steffi Graf in 1991-93, broke Mauresmo in the opening game of the match but eventually lost a tie-break as the Frenchwoman surprisingly gained the upper hand.

Williams has not reached a Grand Slam final since beating her sister Venus at the All England Club 12 months ago, undergoing knee surgery in August 2003.

She lost to Jennifer Capriati in the quarter-finals of the French Open earlier this summer, but looked back to her best when beating Capriati 6-1 6-1 in yesterday's quarter-finals.

Mauresmo, trying to reach her first Grand Slam final since the Australian Open in 1999, was proving a much more resilient opponent and saved two set points before putting away an overhead smash to break back and level at 5-5.

The 24-year-old had clearly rattled Williams, who had lost just 17 games throughout the championships, the top seed missing with a panicky drop shot and making two more unforced errors to give Mauresmo the tie-break 7-4.

Williams had won six of the previous seven matches between the pair, including a 6-2 6-1 victory at the same stage here in 2002, but was staring at defeat when she lost her serve again and trailed 3-1.

Things looked even worse when she went 0-30 down on her own serve in the next game, slamming her racket into the ground in frustration.

However, somehow she won the next three points in a row before the frame of her racket finally cracked, and took the next point with a new racket to reduce the deficit to 3-2.

That looked to be the turning point in the set, Mauresmo losing her serve in the next game and, after Williams held to love, then taking a medical time-out to receive treatment for a back injury.

It seemed to have done wonders when she raced into a 40-0 lead on her serve when play resumed, only to lose the next five points to trail 5-3.

There was still time for more drama, Mauresmo breaking straight back to level the scores at 5-5, but then surrendering her serve again with an horrendous double fault, Williams taking the set 7-5 to take a roller-coaster match into a decider.

Remarkably after five service breaks in the previous set, the first nine games of the decider went with serve with Mauresmo saving the only break point.

But the fourth seed eventually cracked under the pressure, a stunning backhand return winner down the line giving Williams the first match point.

And a wide forehand from Mauresmo gave the top seed a memorable victory to book her place in the final.

Experience counted for little for Davenport against the youthful exuberance of the 17-year-old from Siberia, who melted the hearts of an enthralled Centre-Court crowd by fighting her way back from the brink of defeat.

The leggy Sharapova lost the first set and was a break down to the 1999 champion when a second rain break gave her the chance to re-focus.

The Russian youngster took full advantage to turn the match on its head with a remarkable comeback and Davenport, making her 11th and almost certainly last visit to the All England Club, cast a totally dispirited figure as she trooped off court.

When Davenport hit a forehand long on match point, Sharapova sank to her knees after completing her victory.

Sharapova is the first Russian to reach the women's singles final since Olga Morozova in 1974 and is aiming to become the first woman from her country to win the title.

Yet there was little hint of the drama to come as the 28-year-old Davenport used all her guile and nous to wrap up the first set in just 25 minutes.

Sharapova, described by her coach Robert Landsdorp as a "heaven-born tennis player", dropped her serve in the opening game and rarely looked capable of breaking the dominant Davenport, who had dropped only 18 games in her five matches before this.

Davenport, who has battled her way back from two knee operations to reach a sixth Grand Slam final appearance, was simply awesome in the first set, allowing the youngster just one break point.

By the time the dark clouds descended on SW19 for a second time, Davenport had secured a break in the second set to lead 2-1

But Sharapova, playing more aggressive tennis, kept herself in touch with a love service game which included a second serve ace, and then - almost out of the blue - gained her first break of the match to even things up.

The Russian was quick to pounce on the second serve of her opponent, who put a forehand wide on break point.

Sharapova, fighting for every point, saved break points in each of her next two service games as the set went to a tie-break.

Davenport lost both her two serves and netted a volley to trail 6-3 and, although she saved two set points, another crashing Sharapova forehand broke the deadlock and levelled the match as she took the tie-break 7-5.

The momentum was clearly with Sharapova, whose shrieks became noticeably louder as she moved in for the kill.

She broke her opponent in the first game of the deciding set and, as she piled on the pressure, the confidence visibly drained from Davenport, whose game as well as her serve deteriorated alarmingly.

Sharapova took full advantage of series of unforced errors by the former champion to establish a stranglehold on the match as Davenport totally collapsed.