Finals Day actually began with the doubles final, featuring Eva Birnerova and Tamarine Tanasugarn.
It was Timea Babos and Kimiko Date-Krumm who came out the winners, taking the doubles title, 61 64.
The singles final followed, with Angelique Kerber looking headed for victory with a 64 22 lead.
But Kerber had lost her only prior meeting against Anastasia Pavlyuchenkova, in Brisbane this year.
Pavlyuchenkova won nine games in a row from there to win the second set and lead 5-0 in the third.
After a late surge from Kerber, Pavlyuchenkova finally closed out a 46 62 64 championship win.
The singles and doubles trophy ceremonies are combined in Monterrey - here, the doubles finalists.
Kerber spoke to the crowd as she accepted her runner-up trophy. Kerber was making her debut here.
Pavlyuchenkova is no debutante in Monterrey - in fact she is now a perfect 15-0 at the tournament.
Pavlyuchenkova has won the Monterrey Open all three times she has played, in 2010, 2011 and 2013.
The young Russian posed with her trophy during a photo shoot that took place later in the night.
Earlier in the tournament there was a different trophy presentation for the WTA's Peachy Kellmeyer.
Babos and Pavlyuchenkova were among the players who took the court for Kellmeyer's presentation.
Date-Krumm at the presentation. Kellmeyer was honored for her decades of support for women's tennis.
The tournament also organized the presentation in recognition of the support she has given them.