OSTRAVA, Czech Republic - Qualifier Daria Kasatkina delivered the biggest upset of the J&T Banka Ostrava Open so far, and her best win in 12 months, with a 6-2, 3-6, 6-3 first-round defeat of No.6 seed Elena Rybakina in one hour and 51 minutes.

An intriguing stylistic contrast between rising youngster Rybakina, who has reached a Tour-leading five finals in 2020, and former World No.10 Kasatkina, who has spent much of the past two seasons attempting to regain such form for herself, was ultimately won by the latter's canny defence and superior match management, which captured her first Top 20 win since ousting Aryna Sabalenka in the second round of Beijing last year. Unsurprisingly, the Russian's final numbers - 15 winners to 14 unforced errors, compared to Rybakina's ratio of 35 to 49 - illustrate how watertight her performance was, but not reflected in those statistics is her adeptness at consistently placing the ball in awkward positions on the court.

"I can say that I beat her with tactics," said Kasatkina afterwards. "At the beginning I was trying to play a bit more aggressive to move her - but she was the one who started to move me. "During the match I changed the plan of my game and it worked out very well."

Kasatkina, who spoke in Paris last month about playing with "pure joy" on court after two difficult years in which her ranking slipped from the Top 10 to her current World No.75, also said that she is feeling happy on court again in Ostrava. "After Roland Garros I was mentally a bit down because I'd pushed myself to be ready," she admitted. "After the tournament finished I had a few days when I didn't want to push myself much - but as soon as I came here everything changed. I'm motivated, I feel very good and I'm trying to squeeze the maximum out of this situation. I like the court, I like the surface, I like to play indoors, I like autumn - so everything makes me feel good."

In Rome, the two-time Grand Slam quarterfinalist had first shown signs of her renaissance before an unfortunate ankle injury halted her surge against Victoria Azarenka in the third round. Kasatkina had told the US Open finalist that she had been an inspiration, and she expanded on that today. "Vika had a difficult time for a few years in her comeback - and it really inspired me that she was able to be focused on herself and not listen to the people who were saying she cannot [come back]," said Kasatkina. "She was just working hard and going her way, and in the end she made the amazing run in Cincinnati then the US Open, and after all that she came to Rome and adapted so fast to clay. This story for sure inspires not only me but the people who feel like they are down, like they cannot do something."

In today's match, Rybakina initially controlled the pace. The Kazakh's starting form was hit-or-miss, with breathtaking shotmaking alternating with cheap errors and double faults - but the ratio seemed healthily tilted towards the former. Seven of the 13 winners Rybakina struck in the first set came in the first two games, including two on both break points she faced off the bat, and she was accordingly rewarded with a 2-0 lead.

But two points to consolidate for 3-0 went begging, with Rybakina conceding her lead with a pair of backhand mistakes - triggering a passage of play in which the unforced errors began to flow alarmingly from her racquet. The Hobart champion would rack up 22 in the first set from every corner of the court: a wild smash over the baseline and a brace of double faults led to a love break in the fifth game, and the Rybakina backhand continued to miss its mark as she dropped serve again in the seventh.

By contrast, Kasatkina was in full control of her own game, mixing spin and depth while maintaining enough sharpness to take matters into her own hands to press home her lead: the two-time Grand Slam quarterfinalist only tallied five winners in the set, but three were in closing out her last three service games, including an off forehand on her first set point. From 0-2 down, Kasatkina would reel off seven straight games - including a run of 16 out of 20 points to conclude the opening act - sealing the first break of the second set with a marvellous, inch-perfect lob.

Rybakina did not permit herself to go down without a fight, though. The second set saw the St. Petersburg and Dubai runner-up get her power game clicking - particularly her first serve, which she landed 65% of the time compared to 42% in the opening frame - and reduce her unforced error count to 13, compared to 11 winners.

The 21-year-old also switched up her strategy adroitly, working her way back into the match with finesse rather than continuing to rely solely on power. The net proved a happy hunting ground for Rybakina during this passage of play, and a number of fine dropshots paid dividends - including one to break Kasatkina for 3-1 and take control of the set, and another to seal it on her second set point.

With each player having dominated in turn, the contest was thus poised for a fascinating decider. Unleashing on return, Rybakina struck first - only for her backhand wing to let her down again in the very next game to gift the break back. The fourth game would be crucial: it was here that Kasatkina came up with her most electrifying tennis of the day to break for 3-1, conjuring three phenomenal passing shots as she began to anticipate Rybakina's dropshots and approaches.

This break was decisive: though Rybakina posted a pair of solid holds to keep within touch, Kasatkina's serve did not let her down as the 23-year-old inched towards the finishing line. Maintaining a first serve percentage of 73% over the course of the match, a service winner sealed the win for Kasatkina on her third match point, setting up another popcorn second-round clash against either US Open semifinalist Jennifer Brady or Adelaide runner-up Dayana Yastremska.

Afterwards, Kasatkina also reflected on her career arc since reaching the Top 10 in 2018. "In the past two years I learned a lot," she mused. "In 2018 I said I was experienced - but forget that, I was not experienced at all! Whatever happens in your life, whether you go high or down, everything will make you better - this is how I have to see it. It's always not enough. You have to do more and more, not stop at one thing, especially when you're very young."

2020 Ostrava highlights: Kasatkina unravels Rybakina