ZURICH, Switzerland -- Serena Williams has qualified for next month's season-ending WTA Championships in Madrid.
Williams arrived at the Zurich Open on Monday to discover she was the fifth player to qualify, along with Justine Henin, Jelena Jankovic, Svetlana Kuznetsova and Ana Ivanovic.
The Australian Open champion reached Sunday's final of the Kremlin Cup before losing to Elena Dementieva.
The year-end championship ranking calculations are long and complicated at this point of the season because of the number of players still in the hunt, various injuries that can prevent them from gaining points, and the number of tournaments remaining.
The championship features the season's top eight singles players. At least six other players can still qualify for the remaining berths in the Madrid championships Nov. 6-11.
Williams is among seven of the world's top 10 players at the Zurich event. Reigning champion Maria Sharapova withdrew on Saturday because of a long-standing right-shoulder injury. The tournament also lost Martina Hingis, who pulled out with a hip problem.
Williams, who withdrew from the last two tournaments in Zurich, is slated to play her opening match against local favorite Patty Schnyder on Tuesday. Williams lost in the second round of the 1997 qualification stage and won the doubles event with sister Venus in 1998.
Simply Stunning, Simply Serena
57 Consecutive Weeks as World #1
Olympic Gold Medalist ('00 Doubles w/ Venus)