Sharapova, who won the prestigious end-of-season event in 2004 but whose season has been disrupted by injury, recovered from a slow start to produce some top class tennis, giving her Russian compatriot the run-around at the Madrid Arena.

Sharapova's victory means that Serbia's Ana Ivanovic will join her in the semi-finals from the red group. The two players go head-to-head on Friday to decide who will go through as group winner.

World number one Justin Henin had already booked her place from the yellow group but there was no letting up from the Belgian in her final round-robin match as she demolished a shell-shocked Marion Bartoli 6-0, 6-0 in 57 minutes.

Bartoli, who stepped into the event after Serena Williams withdrew because of a knee injury during her opening match on Wednesday, beat Henin in the semi-finals of Wimbledon this year.

Heaviest defeat
But she was never given a chance to settle as Henin blew her away to with some sublime tennis to inflict the heaviest ever defeat in the 35-year history of the end-of-season Championships and ensure she topped her group.

Sharapova, who has been struggling with a shoulder injury in the latter part of the season, was edged out by the hard-running Kuznetsova in the first set.

But she found her rhythm in the second and started stretching Kuznetsova around the court with some heavy ground strokes, hitting back with breaks in the fifth and seventh games.

In the third set, a Kuznetsova double fault gifted Sharapova three break points in the fifth game which she took at the first opportunity with a brilliant backhand cross-court winner and she broke again in the seventh on her way to a confident victory. -- REUTERS