WASHINGTON, DC, USA - Qualifier Anna Kalinskaya withstood a fightback from Kristina Mladenovic to make her maiden WTA semifinal at the Citi Open, coming through a fluctuating contest 6-4, 4-6, 6-2 in exactly two hours.

"I played twice against [Mladenovic], and I didn't play my best," said Kalinskaya, during her post-match press conference. "So today I really wanted just to play good and enjoy the moment, play point by point. I'm happy that I won. It's a nice feeling."

The Russian had lost in straightforward fashion to Mladenovic twice before on her home turf, falling 6-4, 6-2 on her WTA main draw debut in the first round of Moscow 2016, and then 6-1, 6-3 two years later at the same tournament, but put any memory of those defeats firmly behind her to keep her head as momentum swung from one player to the other.

Kalinskaya, who had lost 12 consecutive WTA main draw matches stretching back to Gstaad in 2017 before this week, becomes the first qualifier in the nine-year history of the tournament to reach the last four - while Mladenovic falls to 0-3 in Washington quarterfinals, having also lost at this stage to Kurumi Nara in 2014 and to Yanina Wickmayer in 2016, as well as to 0-5 in quarterfinals this season.

"I think I improved my game," Kalinskaya admitted. "I tried to play more consistent, just tried to be less in a rush, play more rallies."

With 12 breaks of serve across the whole match, it was Kalinskaya's ability to bring her best tennis on big points that proved crucial: the 20-year-old converted seven of her eight break points while saving 10 of the 15 she faced. Time and again, Kalinskaya would bail herself out of a nervy game with bold, accurate hitting - while by contrast, Mladenovic would repeatedly carve out opportunities with her own trademark power but squander them with loose errors.

"On the breakpoints, I was just trying to let her play, don't miss too much, do less mistakes," Kalinskaya stated. "It worked."

From the off, though, Kalinskaya laid down a marker with her forehand, the day's most reliable shot. The World No.160's clean technique enabled her to find space for winners from that wing - particularly the off forehand - with metronomic regularity throughout the first set-and-a-half. In both sets, an exchange of three consecutive breaks midway through would put Kalinskaya in the driver's seat at 4-2 up, and in both Mladenovic would attempt to reel her in one game later.

But whereas the first set saw Kalinskaya withstand three break points to hold that game and ultimately serve the set out, the Frenchwoman would find more success in her second-set comeback. Her cries of "Allez!" echoed as her forehands skidded past her wobbling rival as she took four straight games to force a decider - although Kalinskaya would still find time for one more audacious play, saving a first set point with a cheeky underarm serve that left Mladenovic floundering.

"I think you know why I did it," smiled Kalinskaya afterwards. "Because I was watching Nick Kyrgios!" It was the first time she had ever tried the tactic in a real match - and its success left her musing that she perhaps needs to begin practising it more.

Mladenovic was unable to sustain her momentum as the third set got under way, wasting three game points to drop serve immediately and then letting a 0-40 opportunity to break back slip past.

The World No.49 would manage to level at 2-2, but her form - intermittent all day, tallying 36 winners to 28 unforced errors - immediately lapsed again. Kalinskaya, breaking again on a netted Mladenovic volley, would then tough out a crucial three-deuce hold to consolidate her lead, coming up with a brilliant backhand down the line to reach 4-2 for the third set in a row.

There would be no fightback from Mladenovic this time, though. Instead, the former World No.10 collapsed in a cascade of double faults, netted smashes and, down match point, a wildly shanked backhand to seal the second Top 50 win of Kalinskaya's career, following her upset of Caroline Garcia in Kuala Lumpur in 2017.

With one milestone firmly under her belt, Kalinskaya now has the chance to set another as she takes on Jessica Pegula in the semifinals. The American overturned her 2016 semifinal result here against compatriot Lauren Davis to win 6-2, 7-6(2) earlier today.

"Before, I was thinking it's important to get to Top 100," said Kalinskaya, who first cracked the Top 200 in September 2016 at the age of 17 and hit a career high of World No.127 in June 2017 - but has yet to take the next step up. "I think I put a lot of pressure on myself. Now I have a new coach [Patricia Tarabini]. She tells me like, 'Anna, try to improve your game and the result will come.' So now I think less about my ranking. I just want to improve."