Defending champion Elina Svitolina has opened her WTA Finals campaign in style with a straight-sets win over world No.2 Karolina Pliskova.

Svitolina’s 7-6 (14-12) 6-4 victory leaves the Ukrainian in prime position to claim a semi-final berth for the second straight season after she won the title last year in Singapore.

The eighth seed needed seven set points to take the opening tiebreaker before sealing victory after one hour and 53 minutes in Shenzhen on Monday night.

Svitolina, who was unbeaten in the finals last year, plays US Open champion Bianca Andreescu and Wimbledon winner Simona Halep in her remaining two pool matches.

Pliskova, who also lost to Svitolina in the pool stages last year, must now beat both Andreescu and Halep in her last two round-robin matches to have any hope of making the semi-finals.

Halep and Andreescu clash in the second Red Group fixture later on Monday.