World number two Maria Sharapova is on the brink of being knocked out of the WTA Finals after losing in straight sets to Petra Kvitova in her second round-robin match in Singapore.

Sharapova went into the year-ending event for the top-8 ranked female players with a slim chance of overtaking Serena Williams on top of the rankings, but a 6-3, 6-2 loss to Wimbledon champion Kvitova further dented that ambition.

And with Caroline Wozniacki getting a 7-5, 6-3 win over Agniezska Radwanska in the other group match, Sharapova is left in a situation where winning her final round-robin match against Radwanska might still not be enough to see her reach the semi-finals.

As it stands, Sharapova would need to win her last match and hope Wozniacki beats Kvitova in the other final White Group match, while also needing to have set and game percentage turn in her favor.

So far, Sharapova has lost her two matches in the group; winning just one set and losing four, while Kvitova and Radwanska have each won a match as well as won two sets and lost two sets.