Elina Svitolina fought back from a set down to claim the biggest title of her career as Sloane Stephens was beaten in an absorbing WTA Finals showdown.

Svitolina recovered from a nervy start in Singapore to defeat the 2017 US Open champion 3-6 6-2 6-2 in a thriller on Sunday.

The fired-up Ukrainian was relentless, prowling around the court with menace as she made it five wins out of five this week to lift the Billie Jean King Trophy and ensure she will end the year fourth in the rankings.

Svitolina has never been beyond the quarter-finals of a grand slam but showed she can deliver on the big stage by grinding down Stephens, who made 45 unforced errors and appeared to run out of steam.

Stephens was bagelled in the first set of her semi-final against Karolina Pliskova on Saturday, but took advantage of a jittering opening from Svitolina in the decider.

The American broke to love when Svitolina blasted a backhand long and the sixth seed had a visit from co-coach Andrew Bettles after going 3-0 down.

An errant Stephens forehand got Svitolina on the board and she showed great resilience to make it 4-2 with a hold from 0-40 down, but thudded a backhand into the net to give the Florida native the opening set.

Svitolina went off court after going a set down and had a first break for a 3-1 lead after a sloppy Stephens service game which included a glaring miss on her forehand.

Stephens unleashed a searing forehand and put away a cushioned volley to end a pulsating rally as she got back on serve immediately, but Svitolina pumped her fist after a third break put her 4-2 up.

The errors were mounting for Stephens, who whipped a backhand into the net to end the second set and a sprightly Svitolina maintained her momentum with a fourth consecutive break, scampering in to guide away an angled forehand winner after the ball looped up off the net.

There was another fist pump from Svitolina when she swatted away a volley to lead 3-0 after fending off three break points as the crowd continued to be treated to rally after rally of the highest order.

Stephens threatened a final twist as she got back on serve at 3-2, but Svitolina broke straight back and pressed home her advantage, dropping to the deck as she celebrated her finest hour when her opponent fired a backhand wide.

STATISTICAL BREAKDOWN
Svitolina [6] bt Stephens [5] 3-6 6-2 6-2

WINNERS/UNFORCED ERRORS
Svitolina – 21/28
Stephens – 24/48

ACES/DOUBLE FAULTS
Svitolina – 0/2
Stephens– 2/1

BREAK POINTS WON
Svitolina – 6/12
Stephens– 3/12

FIRST SERVE PERCENTAGE
Svitolina – 64
Stephens – 71

PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Svitolina – 65/43
Stephens – 53/50

TOTAL POINTS
Svitolina – 95
Stephens – 86