Sania Mirza [Images] had a rollercoaster day at the US Open as she advanced to the quarter-finals of women's doubles with an upset win over former champions Lisa Raymond and Samantha Stosur but crashed out of the mixed event after a straight-set loss in the last-eight stage in New York.

Sania and her American partner Bethanie Mattek [Images] rallied to shock the second seeded American-Australian pair 2-6, 7-5, 7-5 on Monday.

• Images from day 8 | US Open 2007

The 16th-seeded Indo-American duo will next take on fifth seeds Yung-Jan Chan and Chia-Jung Chuang of Chinese Taipei for a place in the semi-finals.

However, the 20-year-old Hyderabadi's campaign came to a halt in the mixed doubles event. Sania and Mahesh Bhupathi [Images] were outplayed 4-6, 1-6 by the Belarussian pair of Victoria Azarenka and Max Mirnyi.

But Leander Paes [Images] made sure that the Indian challenge continued in the mixed competition. Paes and his American teammate Meghann Shaughnessy beat local favourites Ashley Harkeroad and Justin Gimelstob 6-3, 6-4 to advance to the semi-finals.

•  Sania in action at the US Open

They will now be up against the British-American pair of Jamie Murray and Liezel Huber, who defeated Poland's Agnieszka Radwanska and Mariusz Fyrstenberg 6-1, 6-2.

Sania and Mattek's win over the 2005 champions was the highlight of the women's doubles event yesterday.

The Indo-American pair had its back against the wall as Raymond and Stosur broke them thrice to clinch the opening set in just half an hour.

But the momentum shifted in the second set as Sania started to return with more pace and also exhibited better strokeplay at the nets.

Egged on by a partisan crowd, Sania and Mattek finally got a break of serve at 5-5 and served out to even the match.

The decider could have gone either way as there were seven breaks of serve with both sides struggling to hold serve.

Sania had an opportunity to close out the match while serving at 5-4 but she was broken.

However, that hardly made any difference as Raymond and Stosur once again lost their serve, giving Mattek the chance to end the match.

Sania and Mattek did not miss the opportunity this time and held serve to advance.

"We really played solid in the second and third sets," an exuberant Mattek said at the post-match press conference.

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