Keys fought back from 2-5 down in the opening set to upset Kudryavtseva, ranked 81 in the world, and set up a possible second round meeting with Russian top seed Nadia Petrova.

Petrova opens play on Tuesday against compatriot Olga Govortsova.

Keys, who made her professional debut at the US$25,000(S$37,700) Challenger at Fort Walton Beach this month, becomes one of the youngest players to win a WTA match.

American Mary Joe Fernandez holds the record, notching her first victory at 13 years seven months, according to the WTA. -- REUTERS