Sam Stosur was a late starter at the WTA Championships, called-up only after illness forced the withdrawal of defending champion Petra Kvitova. But her quest for a third consecutive semi-final place ended promptly, as Stosur lost her opening round-robin match 6-3, 2-6, 6-0 to Sara Errani.
The Queenslander thus failed to avenge the French Open semi-final loss she counts as the lowlight of a frustrating season. This match ended with Stosur's seventh double-fault on so-called "bagel point", although perhaps the most surprising statistic was that the diminuitive Italian finished ahead 2-1 on aces.
Playing with tape on her right shoulder blade, Stosur hit 26 more winners than her less powerful opponent, but also made 34 more unforced errors in an erratic display. Just when she appeared to have found her rhythm after breaking Errani in the third game of the second set, the ninth seed promptly lost it again at the start of the third, missing a makeable forehand return opportunity on a second serve at break point in the first game, and struggling thereafter.
Errani will now meet Agnieszka Radwanska for the right to progress to the knockout stage. Stosur will take a 2-10 career record into her second match, against unbeaten white group leader Maria Sharapova, although her two wins have come in their past three meetings: one here in Istanbul last year, and the most recent, in the Tokyo quarter-finals.
But with Sharapova having already booked her spot in the semi-finals, and Stosur now unable to advance, the stakes are mostly financial - a winner's cheque for $115,000 - although the Russian second seed will also be keen to progress as the top qualifier from her group to avoid meeting Serena Williams in the crossover, whom she trails 2-9 and has not beaten since 2004.