SINGAPORE - Ace queen Karolina Pliskova got her BNP Paribas WTA Finals Singapore campaign to a fine start by overpowering 2008 champion Venus Williams 6-2, 6-2 in her opening game.

The 25-year-old Czech's victory at the Singapore Indoor Stadium on Sunday (Oct 22), the first day of the US$7 million (S$9.52 million) tournament presented by SC Global, means her head-to-head record over Williams is now 2-1.

Both players put up a display of big hitting from the baseline, but Williams' nine unforced errors to Pliskova's four saw the latter take the set 6-2.

The Czech opened the match with an ace, her 439th of the year, breaking early for a 2-0 lead. Williams, 37, broke back to trail 2-3, but was undone by unforced errors.

At 1-1 in the second set, Pliskova saved three break points to go up 2-1, and more mistakes off Williams' racket eventually gave the world No. 4 the win on her fourth match point.

During their previous encounter at last year's US Open, Pliskova had saved a match point to prevail 4-6, 6-4, 7-6 (7-3) and qualify for her first Grand Slam quarter-final.

In the second match of the day, also in the White Group and featuring power hitters as well, Wimbledon champion Garbine Muguruza had plenty to celebrate after she defeated WTA Finals debutante Jelena Ostapenko 6-3 6-4.

Both players exchanged breaks of serve in the first set, each blasting the ball hard across the net. But world No. 2 Muguruza held steady as French Open champion Ostapenko started to make more unforced errors.

Muguruza, 24, won the first set after a forehand from the seventh-ranked Latvian landed in the net.

The Spaniard held a 5-1 lead in the second set, but three straight good games from Ostapenko narrowed the gap before Muguruza served again for the match at 5-4. The 20-year-old saved two match points, but a backhand into the net handed her opponent the match.