Garbine Muguruza poses with the trophy after beating Serena Williams.  [Photo/Agencies]

Paris - Garbine Muguruza won her first Grand Slam title at the French Open on Saturday defeating top seed and defending champion Serena Williams in the final.

Twelve years younger than the American at 22, and playing in the first clay court final of her career, the Venezuelan-born Spaniard upset the odds to win 7-5, 6-4.

She is the first Spanish woman to win a Grand Slam title since Arantxa Sanchez-Vicario in Paris in 1998 and she is the third straight first time Grand Slam winner after Flavia Pennetta at last year's US Open and Angelique Kerber at the Australian Open.

"I am so excited to play the final of a Grand Slam against one of the best ever players. It's the perfect final and I am so happy," she said.

"I grew up on clay so for Spain and me this is just amazing.