Unseeded Frenchwoman Emilie Loit produced fightbacks in both sets en route to a 7-6 (7/0) 6-4 triumph over Flavia Pennetta in the women's final at the Abierto Mexicano Telcel.
Ranked 52nd in the world, Loit found herself 5-2 down to the number five seed in the first set before storming back and blitzing the tie-break.
She again came from behind in the second set, this time from 4-2, to close out the match and claim her third career title.
"This is a big moment after seven years of coming here," said Loit.
"I'm very happy to win here because it's my favourite tournament.
"It's like a dream, an unbelievable day, a perfect final."
Italian Pennetta, who won here in 2005, was contesting her fourth consecutive Mexico final.
"It got away from me a little," she said.
"I had chances to win but I've played better."