Jankovic's 3-6, 2-6 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.

Also advancing was Chinese wildcard entry Zheng Zie, who followed up her upset of Ivanovic last week to beat 19-year-old Hungarian Agnes Szavay 6-3, 6-4.

Zheng was down 1-4 in the second set and then won five games in a row against the 15th seed before securing her first grand slam quarterfinal berth, joining Li Na as the only Chinese players to do so at Wimbledon.

There she will face Nicole Vaidisova, the 18th seeded Czech causing another upset in seeing off Anna Chakvetadze, the Russia eighth seed, 4-6, 7-6 (0), 6-3.

Another Russian Nadia Petrova, however, made the last eight with a 6-1, 6-4 victory over compatriot Alla Kudryavtseva, who beat Sharapova in the second round.

The Williams sisters, meanwhile, moved closer to another potential Wimbledon final. Defending champion Venus Williams beat Russian teenager Alisa Kleybanova 6-3, 6-4, while two-time winner Serena downed Bethanie Mattek - the only other American left in the draw - 6-3, 6-3.

In men's play, five-time champion Roger Federer swept Lleyton Hewitt - the last man to win the title before him - 7-6 (7), 6-2, 6-4 to extend his winning streak on grass to 63 matches and 38 in a row at the All England Club in London. Federer, who served 21 aces, has now beaten his Australian rival in 12 consecutive matches.

Playing with her left knee heavily strapped, Jankovic was never in serious contention against the 60th-ranked Tamarine. 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.

After converting on match point to reach the quarterfinals of a grand slam for the first time, Tamarine covered her face with her hands and broke into tears.

Jankovic said she played with a tear in her knee sustained during her third-round win on Friday over Caroline Wozniacki.

"I was always a step behind," said the Serb, who committed 19 unforced errors. "It was very hard for me. I tried the best I could and she was quite solid and didn't make any mistakes."

Tamarine will face Venus Williams in the quarters.

Between them, Venus and Serena have won six of the last eight singles titles at Wimbledon. They're in opposite halves of the draw and could meet in the final.