Second-seeded Jelena Jankovic was ousted in straight sets in the fourth round by Tamarine Tanasugarn on Monday, leaving the women's draw without its top three ranked players.

Jankovic's 6-3, 6-2 loss means that none of the top three women reached the quarterfinals — the first time that's happened at a Grand Slam tournament in the Open era. No. 1 Ana Ivanovic and No. 3 Maria Sharapova were upset last week.

Playing with her left knee heavily strapped, Jankovic was never in serious contention against the 60th-ranked Tanasugarn. The 31-year-old Thai, playing in her 12th consecutive Wimbledon, also was treated for a lower back problem during changeovers in the second set.

Defending champion Venus Williams, meanwhile, beat Russian teenager Alisa Kleybanova 6-3, 6-4 to move closer to another potential final against sister Serena.

Williams, a four-time Wimbledon winner, nearly squandered a 5-1 lead in the second set against the 18-year-old Kleybanova. She lost nine points in a row from her third match point in the eighth game and saved three break points at 5-4 before finally closing it with a backhand volley winner.

Williams played on Court 2 — nicknamed the "Graveyard of Champions' for its long history of upsets.

Two-time champion Serena Williams was up next on the same court against Bethany Mattek, the only other remaining American in the draw. The sisters also were scheduled to play doubles together on Court 2 later Monday.