Katerina Siniakova prevailed in one of the longest finals of the year to win the Zavarovalnica Sava Portoroz title Sunday, topping reigning Wimbledon champion and No.3 seed Elena Rybakina 6-7(4), 7-6(5), 6-4.

Siniakova of the Czech Republic took 3 hours and 6 minutes to squeak past Kazakhstan's Rybakina, fighting back from a set and a break down for her third career singles title.

It is Siniakova's first singles title in five years. She won her previous two singles crowns in 2017, at Shenzhen and Bastad.

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The match was the second-longest final of the 2022 season, trailing only Angelique Kerber's 3-hour and 16-minute, 7-6(5), 6-7(0), 7-6(5) victory over Kaja Juvan in the Strasbourg final in May.

It has been a standout year for Siniakova in doubles. She reclaimed the World No.1 ranking this week after she and Barbora Krejcikova completed the career Golden Slam at the US Open. The pair is 18-0 at Grand Slam events this year, also winning the Australian Open and Wimbledon.

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But now Siniakova's singles title haul is also growing with Sunday's comeback victory over Rybakina. Siniakova converted five of her nine break points during the encounter, staving off 43 winners by big-serving Rybakina to triumph.

Rybakina came into the match with a 4-2 head-to-head lead over Siniakova, but despite her winner count, this year's Wimbledon champion was undone by 66 unforced errors as she was unable to finish off the match in two tiebreak sets.

The title wraps up a grueling weekend for Siniakova, who won both her quarterfinal and semifinal matches on Saturday after rain delays forced her quarterfinal to be postponed by a day.

Rybakina zipped to an early 5-0 lead, but signs were already present that Siniakova was ready to battle as she pulled the opening set all the way into a tiebreak. However, a litany of winners allowed Rybakina to claim four of the final five points of the first-set breaker.

Siniakova fell behind by a break at 4-3 in the second set, but the Czech broke back immediately, and once again dragged the set into a tiebreak. This time around, it was Siniakova who eased to the early lead, and she converted her third set point, forcing a wide Rybakina return to level affairs.

In the decider, an early Siniakova break was erased by Rybakina, but the Czech pulled ahead again with another break for 5-4. Serving for the match, Siniakova reached her first championship point after a wide Rybakina forehand, then prevailed at the end of a rally to take the title home.

The singles final finished off a busy Sunday in Portoroz. First, Marta Kostyuk and Tereza Martincova romped to a 6-4, 6-0 win over Cristina Bucsa and Tereza Mihalikova in the doubles final.

Playing just their second event together after pairing up for the first time at this summer's Wimbledon, Kostyuk and Martincova needed just 66 minutes to capture the doubles trophy. It is the first WTA doubles title for both Kostyuk and Martincova.

After the doubles championship, former WTA Doubles World No.1 Katarina Srebotnik was honored on court with an emotional retirement ceremony in her home country.