The WTA's No.2 teen, Keys came into this clash with four Top 20 wins under her belt. And while Italian No.1 Errani had her best Grand Slam showing here with a run to the final in 2012, in addition to a semifinal outing last year, she was still only 3-3 in French Open first round matches before Tuesday.
Keys' clay court season has been highlighted by her third WTA semifinal last week in Strasbourg, while Errani was a semifinalist in Stuttgart and runner-up in Rome.
Keys rallied from 5-1 down in the first set to knot it at 5-5, but Errani promptly broke serve and held to take the set. Keys then got the momentum again by capturing the second set, but Errani quickly righted the ship and from 1-1 in the third set did not surrender another game in her 7-5, 3-6, 6-1 triumph.
By The Numbers
Errani's 12 winners were far less than Keys' 53, but she had just 12 unforced errors compared to Keys' 69. She also converted on both of her break point chances in the third set and six of nine for the match.
"Thanks for all the support," Keys tweeted. "The crowd was amazing. Got to keep getting better."
Errani squares off with Germany's Dinah Pfizenmaier for the first time. Though there is still plenty of competition in her section of the draw, the loss of World No.2 and potential quarterfinal opponent Li Na could bode well for Errani's Roland Garros campaign.