The world number one pair of Sania Mirza and Martina Hingis will today play its second round-robin match of the year-ending WTA Finals in Singapore. The Indo-Swiss duo will take on the seventh placed Czech team of Lucie Hradecka and Andrea Hlavackova.Sania and Hingis had, on Monday, won their opening match against the American pair of Raquel Kops-Jones and Abigail Spears 6-4, 6-2.Top-8 players and pairs of the year, divided into two round-robin groups – red and white – participate in the WTA Finals each year. Sania and Hingis are in the red group.Top two from each group progress to the semi-finals, which will be followed by the Final. Sania had won the tournament last year with Zimbabwean Cara Black.Sania and Martina, as a pair, have won 8 titles this season, including Wimbledon and the US Open.