Kessler thrived as an underdog in the tournament, ousting No. 4 seed Xinyu Wang of China and No. 5 seed Anastasia Potapova of Russia before completing the upset of Haddad Maia.

On Saturday, Kessler didn’t get into a groove until the second set, where she took six games in a row after falling behind 1-0. The 25-year-old then trailed 3-1 in the third set before rallying for the win over Haddad Maia, who entered the match ranked No. 23 in the world.

Kessler won 32 of 46 first-serve points and matched Haddad Maia in aces and double faults with three and four, respectively.

Sixth-seeded Linda Noskova of the Czech Republic won her first career WTA Tour title, defeating New Zealand’s Lulu Sun 7-6 (6), 6-4 in the final in Monterrey, Mexico.

After trailing 6-5 in the first set, Sun forced a tiebreaker, where she let a 6-4 lead slip away as the 19-year-old Noskova broke Sun twice, with the second break giving her the set.

At 2-2 in the second set, Noskova broke Sun’s serve and held off a comeback attempt by the unseeded New Zealander, who was playing in her first WTA Tour final. Sun, 23, produced 13 aces to Noskova’s four but committed five double faults.