Tennis: Graf wins thriller

Steffi Graf won a thrilling second-set tie-break 13-11 against the Olympic champion, Lindsay Davenport, to reach the semi-finals of the season-ending Chase Championships in New York.

Graf, the holder, pressured by the big groundstrokes of the American, overcame deficits in each set to win 6-4, 7-6 in one hour and 40 minutes on the blue carpet at Madison Square Garden on Thursday night.

A third successive groundstroke error by the weary Davenport finally gave Graf victory on her fourth match point of the tie-break after Davenport had squandered five set points during a tense finale. "I was a little nervous at the start," said Graf, who again showed no ill effects from a back ailment that forced her to quit in last Sunday's final in Philadelphia.

The Corel WTA Tour has announced a new rankings system designed to encourage top players to compete more often. The system, which takes effect from the week beginning 23 December, is based on total points earned over a 52-week period rather than on an average of points based on playing a minimum number of events. Players will be required to play a minimum of 12 tour events apart from the Grand Slams and season-ending championships in order to qualify for a full share of bonus pool money at the end of the season.