SINGAPORE — Playing her first match as the top-ranked player, Simona Halep beat Caroline Garcia 6-4, 6-2 at the WTA Finals on Monday.

"I am really happy I can win the first match (as No. 1)," said Halep, the first Romanian woman to be top-ranked. "It takes the pressure off."

Also, Caroline Wozniacki of Denmark, the 2010 runner-up, never surrendered in beating Elina Svitolina of Ukraine 6-2, 6-0 for the first time in four matchups.

"I just kind of broke her down a little bit," Wozniacki said. "Then she lost the belief or she tried to go a little bit more for it. She just couldn't find a break or find a way to break me."

All three players making their WTA Finals debut - Garcia, Svitolina, Jelena Ostapenko - lost their first round-robin matches in straight sets.

Halep faced six break points and lost only one when she conceded her serve with a double fault in the sixth game.

Garcia, making her WTA Finals debut, was broken twice in each set.

Halep, making her fourth consecutive appearance in the WTA Finals, was a finalist here in 2014. She lost to No. 1 Serena Williams, which marked the last time the top-ranked player won the season-ending event.

Svitolina, the first Ukrainian woman to play at the WTA Finals, arrived in Singapore having won a tour-leading five titles this season.

"Today was a terrible day for me," Svitolina said. "Caroline played really, really good. It was probably my worse match I've played in a couple of years."

Halep and Wozniacki stand at 1-0, while Garcia and Svitolina are 0-1 in Red Group action.