Doha, Feb 24 (IANS): Indo-Swiss top tennis pair Sania Mirza and Martina Hingis expectedly romped home into yet another quarterfinal -- their 41st successive win on the circuit -- but not before getting a scare in their second round win in women's doubles at the $2.8 million Qatar Total Open here.

Unseeded Chinese pair Yi-Fan Xu and Saisai Zheng fought hard but the much experienced top seeds came out better, winning 6-4, 4-6, 10-4 in an hour and 25 minutes on the outdoor hard courts of the Khalifa International Tennis and Squash Complex on Tuesday night.

Sania and Martina, who got a first round bye, have not lost a single match this year, having won four tournaments earlier in Sydney, Brisbane, St. Petersburg and the Australian Open in Melbourne.

The first set was extremely topsy-turvy with service games broken as many as seven times, with both pairs making a number of unforced errors. 

The world's highest ranked team was also broken as many as three times but they were better in their return games. They broke the Chinese team four times to get the edge and clinch the set.

Sania and Martina's game went down in the second set as they failed to even earn a single breakpoint opportunity. On the other hand, they give away five chances. 

Though they saved four of them, Xu and Zheng did well to convert one breakpoint chance which was enough to seal the set in their favour to push the match into the decider.

The Indo-Swiss combine, nicknamed 'SanTina' by their fans, came out with their best when it mattered the most as they took the all-important super tie-break 10-4 to clinch the set and match.