WTA World Tour Finals results

Svetlana Kuznetsova beat fellow Russian Elena Dementieva at the Sony Ericsson Championships in Doha - to send Venus Williams into the semi-finals.Dementieva could have qualified from the Maroon Group with a win, but she played poorly in a 6-3 6-2 defeat. Earlier, Jelena Jankovic reached the last four with a 6-2 6-2 rout of Caroline Wozniacki in the White Group.

Denmark's Wozniacki progressed after Victoria Azarenka retired due to cramp when trailing Agnieszka Radwanska. Defending champion Venus joins her sister Serena as the two players qualified from the Maroon Group to reach Saturday's semi-finals.

Venus will face Jankovic, while Serena plays Wozniacki for a place in the final of the $US4.55m tournament with the eventual champion taking home (£944,000).