Second seeds Sania Mirza and Yaroslava Shvedova made a shock first-round exit from the AEGON Classic in Birmingham on Thursday.
The Indo-Kazakh pair lost 5-7 3-6 to the unseeded Czech-Russian pair of with a straight-set defeat against Iveta Benesova and Alla Kudryavtseva in the first round of the grass-court event.
Sania and Shevdova, who won College Park doubles title last year, lost the contest in one hour and two minutes.
Sania was playing with a fifth different partner this season. She had teamed up with Elena Vesnina, Roberta Vinci, Bethanie Mattek-Sands and Anastasia Rodionova before.
Nadal slips on grass
Halle: Newly-crowned French Open champion Rafael Nadal's start to the grasscourt season at Halle was cut short when the top seed crashed out in the quarterfinal to Germany's Philipp Kohlschreiber.
Kohlschreiber, ranked 28 in the world and defending champion here, notched up his first-ever victory over Nadal in nine encounters, winning 6-3, 6-4.
The German will now play the winner of the match between Czech ace Tomas Berdych and Germany's injury-prone former world number two Tommy Haas. Nadal had captured a record seventh Roland Garros title on Monday.
The loss halted Nadal's 13-match win streak, which saw him triumph over Novak Djokovic in both the final of Rome Masters, and the Roland Garros final. His previous defeat came to Fernando Verdasco in the third round of the Mutua Madrid Open.