Caroline Garcia has become the first qualifier to reach a WTA 1000 tournament final after continuing her dream run at the Western & Southern Open with a hard-fought win over sixth seed Aryna Sabalenka on Saturday.

In a match halted twice for extended periods by rain, Garcia triumphed 6-2 4-6 6-1 in the semi-final that lasted two hours and five minutes.

Garcia's victory over Sabalenka secured her spot in the decider against Petra Kvitova, who beat Madison Keys in the other semi-final earlier on Saturday.

The victory also adds another top-10 scalp to Garcia's list from this week's Cincinnati event, having knocked out fourth seed Maria Sakkari and seventh seed Jessica Pegula en route to the final four.

The world number 35 had also beaten top-ranked Iga Swiatek during a run to the Poland Open title three weeks ago.

Garcia has a Tour-leading 26 main-draw victories since June with title wins in Bad Homburg and Warsaw in that stretch; next most match wins in that stretch is Simona Halep (19) and Beatriz Haddad Maia (17).

Saturday's win was fueled by a strong first-serve points won percentage of 81.3 per cent for Garcia, sending down 8-4 aces while Sabalenka was not helped by 7-1 double faults.

The 28-year-old, whose highest rank was fourth in 2018, saved seven break points while converting six of the 13 she generated.

She had to come through qualifying to earn a place in the Cincinnati main draw and looked like racing past Sabalenka after taking the opening set in impression fashion.

A two-and-a-half-hour rain delay halted Garcia's progress at 1-1 in the second set, and it was Sabalenka who returned the strongest from the break.

Garcia needed her left arm bandaging when trailing 5-4 in the second set, forcing Sabalenka to endure a long wait to serve to level the match.

Just as the match looked to be tilting the Belarusian's way, an improved Garcia broke to lead 3-1 in the deciding set; however, rain returned in the next game with Garcia 30-15 up on serve, causing another hold-up.

But Garcia would not be denied after play resumed approximately 90 minutes later, winning the final three games to secure an historic place in the decider.

Petra Kvitova fended off home favourite Madison Keys to reach the Western and Southern Open final and secure a return to the world's top 20.

The two-time Wimbledon champion battled to a 6-7 (6-8) 6-4 6-3 victory in two hours and 18 minutes, saying the match had been "mentally so tough".

Both players had taken significant scalps to reach this stage, with Keys knocking out world number one Iga Swiatek and Kvitova ousting Wimbledon runner-up Ons Jabeur.

Kvitova reached semi-finals at Cincinnati in 2012 and 2018 and lost three-set battles on both occasions, but this time she came good in the decider to earn a first final appearance at the event and a 40th overall in her WTA career.

The 32-year-old Czech slipped an early break adrift in the opening set before fighting back to force a tie-break. She came from behind in that, too, to level up at 6-6, only for hard-hitting American Keys to win the next two points, the first with a sizzling backhand winner.

Kvitova sensed she was still firmly in the match, however, and surges to 3-1 in each of the next two sets provided the platform to fully turn around the contest.

A 12th WTA 1000-level final awaits her, and she will go to 20th in the rankings should she lose Sunday's final and up to 15th if she carries off the title.

Kvitova said of her win: "It was incredibly tough. I expected it would be tough, but I didn't expect it that tough. Madison played unbelievable.

"She played an amazing tie-break, but I tried to keep going, be there and be a little calmer than before and wait for the chances. It was an incredible match, and I'm really happy that I made it somehow.

"I don't really care about the ranking. Being in the final, that's more important, and that's why I'm playing tennis: to be in finals and fighting for a trophy."

She awaited the winner of the second semi-final between Aryna Sabalenka and Caroline Garcia.

Madison Keys stunned top seed Iga Swiatek 6-3 6-4 to book her place in the quarter-finals of the Western & Southern Open on Thursday.

Keys arrived in the contest seeking a first career victory over a reigning world number one in six attempts, having failed to win a set in each of the previous five.

The 2019 champion had also lost her previous two showdowns with Swiatek, including a resounding 6-1 6-0 defeat in the Indian Wells Open quarter-finals earlier this year.

After the first games went with serve, Keys went into overdrive; reeling off nine successive games to take full command of the contest at 6-3 5-0.

Swiatek rallied as she rescued match point to avoid the bagel, winning 11 of 12 points to reduce the second-set deficit to 5-3.

The winner of six WTA titles this season, the Pole saved a further match point in the ninth game before claiming what appeared to be another crucial break of serve.

However, former US Open finalist Keys responded magnificently to make it third time lucky against Swiatek, who is now 4-4 since her 37-match winning streak ended with defeat by Alize Cornet at Wimbledon.

Emma Raducanu admitted she has been "too tense" in recent defeats and is aiming to play more freely as she prepares to defend her US Open title.

Raducanu has struggled to follow up last year's shock win at Flushing Meadow, but she appears to have hit form at just the right time.

The 19-year-old has beaten both Serena Williams and Victoria Azarenka in straight sets during this week's Western and Southern Open in Cincinnati, dropping just four games against Williams and two against Azarenka.

Her win against Azarenka on Wednesday was just Raducanu's third career victory against a top-25 opponent, after beating Belinda Bencic and Maria Sakkari on her way to winning last year's US Open.

Speaking after her win against the Belarusian, Raducanu said: "I think I have tried a lot of things, and this year I think some matches, I have lost a lot of matches from leading situations and probably just played too tense.

"I think that I just need to swing, and I just said that these two tournaments, or this tournament especially, I'm just going to swing freely and take that and see what happens."

Raducanu also said she will wait until after the tournament to reflect on beating two multiple grand slam champions with relative ease.

"I think after the tournament I actually have to take a step back and be like, 'Look, you just beat two unbelievable champions'," she said. "It's a pretty good achievement. You know how difficult the wins are to come by."

The number 10 seed will face seventh seed Jessica Pegula in the third round in Cincinnati on Thursday.