CHARLESTON, SC, USA -- No.5 seed Caroline Wozniacki of Denmark continued to improve her excellent record at the Volvo Car Open on Saturday with a 6-3, 6-4 semifinal win over No.16 Petra Martic of Croatia, advancing to the championship match in Charleston for the third time in her career.

"I think I served well in most of the match and I think I returned really well most of the match as well, and I just tried to stay aggressive as much as I could and tried to make [Martic] run and make her move," Wozniacki told the press, after her win. "I think I did well today."

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2011 champion and 2009 runner-up Wozniacki has the most career match victories in Charleston out of any player who participated in the main draw this year. The former World No.1’s win over Martic garnered her a 19th match win at the Volvo Car Open.

"It's been a long time since I made this long run here," said the former titlist. "So I'm just really happy to be through to the finals once again, and I've been feeling great this week."

World No.13 Wozniacki came into the match with a 5-0 head-to-head lead on World No.53 Martic, and in fact had never lost a set to the Croat. Just one break separated the two players in each set, but Wozniacki emerged triumphant in straight sets once again after one hour and 25 minutes of play.

Wozniacki had 21 winners to only 13 unforced errors on the day, while Martic's 19 winners were overridden by 24 miscues. Wozniacki was strong in her service games for most of the match, winning 75 percent of points on her first serve and not having to face a break point until midway through the second set.

"I just keep needing to have a positive attitude, because I can play well on this surface," Wozniacki stated. "I think I just need to keep working on my movement and keep working on my game so that I keep improving every week."

In her first final of the season, Wozniacki will face No.8 seed Madison Keys of the United States, who dispatched Monica Puig of Puerto Rico in the second semifinal. Keys is also into her first final of 2019. Wozniacki has won both of her prior meetings with Keys, but this will be their first encounter on clay.

"Both of them play very aggressive tennis," Wozniacki deduced, before the other semifinal was played. "Both of them prefer their forehands and have big forehands, and Madison has a big serve and looks to run around that forehand a lot, whereas, Monica will move around the forehand a little less. But, yeah, both playing aggressive, and I need to be ready from the start."

Wozniacki had a tricky service game at 1-1, getting pushed from 40-0 to deuce by Martic’s firm groundstrokes, but the Dane was able to close out the game with an ace to garner the hold. That would be Wozniacki’s only tough service game of the set, as she did not face a break point throughout the opening frame.

Martic used her ferocious down-the-line forehand with aplomb to keep the set close, but the Croat faltered at the very end of her service game at 3-2. Martic saved two break points in that game with a dropshot and a beautiful backhand, but Wozniacki clinched the 4-2 lead on her third chance after a divine crosscourt forehand winner up at net.

That single break was all that Wozniacki would need to seal the first set, as the former World No.1 placed her shots perfectly and took control with well-timed excellent deliveries. Wozniacki had six aces in the opener, three of which came on game points, including her first set point.

Wozniacki maintained her momentum at the start of the second set, as she attained her first break of that set to lead 2-1 after Martic sent a backhand wide down break point. After a stirring pep talk from her coach Sandra Zaniewska, Martic continued to fight, coming back from 0-30 down to hold for 3-2 as drizzle started to fall.

Martic held at love for 4-3 and was rewarded for her persistence, when unforced errors from Wozniacki handed the Croat her first three break points of the match. Another wide backhand from Wozniacki gave Martic new life, as the No.16 seed finally broke the Dane and achieved parity in the set at 4-4.

But the steely Wozniacki was unfazed, and pulled off another break in the following game, putting away a forehand for 5-4. Serving for the match, a rally forehand by Wozniacki forced an error from Martic at 30-30, setting up match point for the former World No.1. There, a backhand error by the Croat ended the closely-contested clash.