TORONTO, Canada - Daria Kasatkina completed a topsy-turvy win over former World No.1 Angelique Kerber early Tuesday morning at the Rogers Cup, rallying from a set down to win, 0-6, 6-2, 6-4.

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The young Russian has endured a largely disappointing season after finishing 2018 ranked inside the Top 10, but showed signs of her best tennis against Kerber, tying up their eight-match rivalry after one hour and 57 minutes on Centre Court.

"It was very difficult because of the lights, and I had warmed up in the sun," Kasatkina explained after the match. "We didn't go on the court for another five hours, so that was very tough, but in the end, I was happy to turn the match and win in the end."

Kasatkina lost in straight sets to Elina Svitolina last week at the Mubadala Silicon Valley Classic, and appeared on course for a similarly quick defeat against Kerber, who raced through the opening set - allowing the Russian just 15 points as she struck an even eight winners to eight unforced errors.

"Even after I lose 6-0 in 25 minutes, I didn't lost my concentration, and with my attitude, I was always supporting myself, saying I could turn the match. That was the key, and this is what my coach was telling me to do."

The Russian found her range in the second set, hitting eight winners of her own and reducing her unforced errors (11 in the first to just six in the second) as she soon leveled the match against the three-time Grand Slam champion.

"I didn't change much. I was just trying to put more balls inside the court and play more rallies so I could feel the ball better. In the end, it worked, and I'm happy."

Kasatkina took that momentum into the decider with a quick 2-0 lead, but it was Kerber who responded by reeling off three straight games of her own, getting within two points of a 4-2 advantage.

Unseeded in Toronto, Kasatkina turned the tables once more and won four of the final five games, reversing a 40-15 deficit as Kerber served to stay in the match to secure victory on her second opportunity.

In all, she struck 16 winners to 32 unforced errors and converted five of 10 break point chances. While Kerber had more winners, she also had more errors, ending the clash with 24 and 45 of each.

"It feels great!" Kasatkina said of her second Top 20 win of 2019. "For the moment, I'm thinking more about going to sleep, but of course, I'm happy because it was a very tough match and we were both fighting. In matches like this, sometimes luck decides."

Up next for the 22-year-old Kasatkina will be the winner of an all-Canadian battle between former Wimbledon finalist Eugenie Bouchard and reigning BNP Paribas Open champion Bianca Andreescu, who has been off the tour for much of the past five months due to a nagging shoulder injury.

"They're both super aggressive. Maybe this is the Canadian school of tennis. For sure, we'll be playing on a big court, which I like a lot. There'll be a lot of people there, and I like matches like this. I've practiced with Eugenie a few times, but it'll be tough, no matter who wins."