CHARLESTON, SC, USA -- No.8 seed Madison Keys of the United States moved into the Volvo Car Open final for the second time in her career on Sunday, after a rain-interrupted 6-4, 6-0 semifinal victory over Monica Puig of Puerto Rico.

Keys had split her four previous encounters with 2016 Olympic champion Puig, but nudged ahead in their head-to-head after 85 minutes of play, which included an hour-and-a-quarter rain delay midway through the opening set.

Photos: Vive la difference! 14 titles, 14 winners in 2019 so far

"I think [Puig] came out really firing and going for her shots, and she was making a lot of them," Keys said, during her post-match press conference. "So it was just weathering the storm and waiting for opportunities and trying to play smart when I got them.

"And I think the rain delay actually really helped because I got to refocus and kind of take a step back. And then in the second set, it was really just, stay on it, stay on it, try not to think about anything else. Just really happy that I was able to close it out."

Keys, who reached the final in 2015 before falling to Angelique Kerber, had 29 winners, including nine aces, to just 17 unforced errors in the clash, as she reeled off the final eight games to zip to victory. Keys claimed 73 percent of points on World No.63 Puig's second service.

World No.18 Keys will take on 2011 Volvo Car Open champion Caroline Wozniacki of Denmark in the final on Sunday, after No.5 seed Wozniacki moved past No.16 seed Petra Martic of Croatia in straight sets in Saturday’s earlier semifinal. Wozniacki leads Keys 2-0 in their head-to-head, but this will be their first match on clay.

"Definitely going to look at how [Wozniacki's] been playing and just try to have a really great game plan," said Keys. "But more than that, just focused on myself, and I'm really proud of what I've done this week and how I've bounced back from a couple of tough losses. So I'm just going to go out and try to have some fun."

The eighth seed started the match strongly, holding her first two service games with ease and then, after having two break points in Puig’s opening service game, broke for a 3-1 lead after Puig fired a forehand wide on her second break point of that game.

Puig, however, struck back quickly at 4-2, earning double break point after a series of forehand winners, then pulling back on serve at 4-3 after Keys blasted a wide backhand miscue on Puig’s first opportunity. Following that game, the rain which had been threatening play came through in full force, and the match was halted for about an hour and 15 minutes.

Upon resumption, Puig won a third consecutive game, but Keys stopped her streak by holding for 5-4 with a backhand crosscourt winner. In the next game, aggressive returns from Keys brought her to double set point, and although Puig pulled back to deuce, an error from the Puerto Rican gave Keys a third chance, which she converted with a huge forehand service return.

Puig was unable to get rolling in the second set, double faulting away her first service game to fall behind a quick break at 2-0. Keys started to ease through the rest of the match from there, clinching a second break with a forehand winner to go up 4-0.

As the rain started to move into the area once more, Keys came close to dropping a game. The No.8 seed faced a break point at 4-0, but got out of that predicament by blasting an ace, then crushing a forehand winner two points later to hold and keep her game-winning streak alive.

At 5-0, it became Puig’s turn to struggle on serve as the mist intensified. Nevertheless, Puig saved three match points in the game before Keys used a netcord ball to fire another forehand winner and reach a fourth match point. On that occasion, Keys slammed a huge forehand return to force a netted error from Puig, winning her eighth straight game to polish off the win.