Abu Dhabi, Feb 7 (IANS): Indian tennis ace Sania Mirza and her American doubles partner Bethanie Mattek-Sands bowed out of the Abu Dhabi Open WTA 500 tennis tournament, which was the Indian star's penultimate event of the career.

Sania and Bethanie lost to Belgian-German pair Kirsten Flipkens and Laura Siegemund by a 3-6, 4-6 scoreline in the opening round of the women's doubles on Monday.

The loss brings six-time Grand Slam winner Sania closer to her retirement as she has announced to hang up her racquets after the Dubai Tennis Championships, which starts on February 27, where another American Madison Keys will be her partner in women's doubles.

Last month, Sania wrapped up her glittering Grand slam career in Australian Open as mixed doubles runner-up. The Indian ace and partner Rohan Bopanna suffered a 7-6(2), 6-2 loss at the hands of the all-Brazilian pair, Luisa Stefani and Rafael Matos.

Interestingly, Sania claimed her first major in 2009 at Melbourne Park, when she paired up with Mahesh Bhupathi. And she ended her illustrious Grand Slam career at the same venue.

From 2009 to 2016, Sania Mirza won six Grand Slam doubles titles - three each in the women's doubles and mixed doubles. In 2015, she even became the world's No. 1 in women's doubles ranking.

"The journey of my professional career started in Melbourne in 2005 when I played Serena Williams in the third round as an 18-year-old," a teary-eyed Sania said after the Australian Open mixed doubles final.

"That was scarily enough 18 years ago and I've had the privilege to come back here again and again and win some titles here. There's no better place and no better person to finish my Grand Slam career with."