Elena Rybakina leads the Hologic WTA Tour with 25 wins this year. She is the only player to have beaten No.1 Iga Swiatek and No.2 Aryna Sabalenka.

So what could possibly motivate her to raise her game another level in Sunday’s final (1 p.m. local time) of the Porsche Tennis Grand Prix? How about the gleaming Taycan 4S Sport Turismo electric car that goes to the winner?

Rybakina, who has yet to secure her driver’s license, thinks that might spur her into action.

“I wanted to do it already long time, but I never have chance to be at one place for long,” she told reporters Saturday. “I did already couple of lessons. I was driving, but for sure that’s the goal for this year outside of the court.

“And with this car, if I win, it’s going to be one double goal.”

'I don't have a driver's license': Rybakina cracks up the crowd in Stuttgart

Rybakina, who defeated Swiatek 6-3, 4-6, 6-3, meets unseeded Marta Kostyuk, a 7-6 (2), 6-2 winner over Marketa Vondrousova.

Who will win this prelude to next week’s Mutua Madrid Open?

The gloves are off. Sides are being taken. Courtney Nguyen and Greg Garber debate the merits of the two candidates.

Advantage, Rybakina 

Yes, Swiatek has a firm grasp on the No.1 ranking. And yes, No.2 Sabalenka may be the latest Grand Slam champion. But Rybakina is putting up stats that reaffirm her place among the three-player pack that has pulled away from the field over the past two seasons.

It's been 14 years since a player made five finals in the first four months of the season (Victoria Azarenka, 2012). That’s where Rybakina now stands. Stuttgart is her fifth final of the year and her three-set win over Swiatek in Saturday’s semifinal produced that tour-leading 25th of the season.

It has required exceptional feats this season to beat Rybakina, who Sunday will look to capture a tour-leading third title of the year and eighth overall. It took an historic effort by Anna Blinkova to knock her out of the Australian Open. Swiatek had to play a 90-minute set and save a set point to edge her in Doha. Danielle Collins in the Miami final? Who hasn’t been losing to Collins?

Road to the Stuttgart Final: Rybakina soars into her fifth final of the year

Rybakina will be the overwhelming favorite. The only players to beat her since the Australian Open -- Swiatek and Collins -- have possessed firepower that won't be an issue for her Sunday against Kostyuk. Rybakina won their last match 6-2, 6-1 at the US Open last year.

The indoor conditions in Stuttgart feed right into Rybakina's power game. She smacked 10 aces past Swiatek in the semifinals. She's battle-tested, too. She's saved 64.5 percent of the break points she's faced, up from her season average of 61.6%. And she's now on an 11-match win streak in completed three-set matches.

And for all the concerns that clay is her least desirable surface, Rybakina has been quick to remind reporters in Stuttgart that her first WTA title came on clay, and she picked up her second WTA 1000 title last year, in Rome. She beat Swiatek on the way to that one, too. -- Courtney Nguyen

Advantage, Kostyuk

While that wonderful semifinal between Rybakina and Swiatek felt like a final, there’s still one more to play. Don’t make the mistake of underestimating Kostyuk, for she has already personally escorted Zheng Qinwen, Coco Gauff and Marketa Vondrousova to the exit.

If you’re scoring at home, you know that’s three Top 10 players. Rybakina would be a fourth -- in four days. How crazy is this run for the 21-year-old from Ukraine? She lost her first 13 matches against Top 10 opposition. Coming into the tournament, she had a total of four Top 10 career wins. The wins over Zheng and Gauff were her first back-to-back Top 10 wins. If she takes the final, it will be back-to-back, back-to-back Top 10 wins -- a personal best and a possible record for hyphens in a sentence.

In any case, Kostyuk has the adrenaline/momentum edge.

Road to the Stuttgart Final: Kostyuk reels off a trio of Top 10 wins

This, Rybakina understands.

“If it’s going to be Marta, she has nothing to lose,” Rybakina said. “She comes, she’s going to swing, and she moves really well. So she already beat good players. It’s going to be tough one, for sure.”

Kostyuk has shown some remarkable intestinal fortitude this week, saving five match points against Zheng and converting her eighth match point to defeat Gauff. The match against Vondrousova, your reigning Wimbledon champion, was similarly complicated. Up 5-1, Kostyuk managed to squander three set points and fall back into a tiebreak. It was 2-all, when she won the last five points to take the extra session.

Kostyuk has been playing the best ball of her life this year and the numbers back it up. She’s 19-6 and she’s already guaranteed herself a career-high ranking. Kostyuk is currently No.27 and a win would place her inside the Top 20.

Perhaps her biggest achievement against Vondrousova was avoiding a third set. Previously, Kostyuk had gone the distance in all three matches but this time she got off in 95 minutes -- more than an hour less than Rybakina, who herself has played three straight three-setters.

Considering her underdog status, the 1-1 head-to-head history works in her favor. Rybakina won their most recent match, in the first round of last year’s US Open, but Kostyuk won the first, earlier the same year in Adelaide. -- Greg Garber