Jessica Pegula will rise to third in the world rankings after defeating Maria Sakkari 6-2 6-3 in the final of the Guadalajara Open on Sunday.

It is surprisingly only the second singles title of Pegula's career on the WTA Tour, and the 28-year-old's first WTA 1000 title.

Against Sakkari, the American showcased her complete game, controlling the opening set with her serve before using her powerful returning ability to close things out.

In the first set, Pegula converted 10 of her 11 accurate first serves into points, winning 76 per cent of her total service points while facing no break opportunities. She only had two break point opportunities herself, and she took both.

Her success rate on service points dropped to 60 per cent in the second set, but she made up for it with her returns, winning 55 per cent of the points on Sakkari's serve while breaking three times to pull away.

It caps off a remarkable week for Pegula, who collected straight-sets wins over top-50 opponents Victoria Azarenka, Sloane Stephens and Bianca Andreescu in her three matches leading to the final.

While it was the last tournament of the season, both Pegula and Sakkari finished in the top-eight for world ranking points this season and therefore have qualified for the WTA Finals, beginning on October 31.