Caroline Wozniacki's defence of her WTA Finals title is over following a 5-7 7-5 6-3 defeat to Elina Svitolina, who tops the White Group with a perfect record.

Wozniacki arrived in her final round-robin match knowing only a straight-sets win would be enough to keep her campaign alive in Singapore.

But, after battling hard to take the first set, Wozniacki's fate was sealed when she lost the second, and Svitolina finished ahead of fellow qualifier Karolina Pliskova in the final table by taking the third.

The match got off to a promising start for the Dane, who immediately put Svitolina under pressure by racing into a 0-40 lead in the opening game.

Svitolina escaped on that occasion but was soon a break down after Wozniacki established an equally impressive cushion in the third.

The Ukrainian hit back to leave Wozniacki serving for her place in the tournament at 5-4 down.

Wozniacki rose to that challenge and a wide Svitolina forehand in the next gave her the upper hand once more, as she went on to wrap up the opening set.

The second was a similarly tight affair, Wozniacki again staring at elimination at 5-4 down on serve, but she could not replicate the late flourish she managed in the first.

After pulling level at 5-5, Wozniacki failed to break Svitolina in the next and fell 15-40 down as she served to keep her semi-final hopes alive.

Svitolina squandered the two set points - the second when a backhand floated agonisingly long - but she clinched her place in the last four on her fifth set point, Wozniacki sending a backhand of her own beyond the baseline.

Wozniacki had little to play for in the deciding set but put up a good fight, Svitolina eventually making the decisive break in game eight to clinch a hard-fought win.