Strasbourg, France (SportsNetwork.com) - Top-seeded American Madison Keys had to come back from the brink to sneak out a second-round win Wednesday at the Strasbourg International, a final clay-court French Open tune-up.

The Australian Open semifinalist outlasted Croatian veteran Mirjana Lucic- Baroni 4-6, 7-6 (7-3), 7-6 (7-0) at Strasbourg Tennis Club. Keys was down a set and trailing 0-5 before mounting an incredible comeback.

"I was definitely thinking that I would be heading to Paris," Keys said. "Mirjana was playing well and I wasn't playing great, and I was just really happy that I was able to find it and figure it out.

"For sure my mental toughness was important. Even at 5-0 I was trying hard and putting in all of my effort. My game was there, it was just a couple of points here or there that hadn't been going my way. It was a battle to the very, very end, and I'm very relieved with this victory. Hopefully I can build on it and play better tomorrow."

Key's quarterfinal opponent on Thursday will be French crowd favorite Kristina Mladenovic, who tackled Keys' compatriot Alison Riske 7-6 (7-4), 6-2 on Day 4.

Also in the second round, Russian Elena Vesnina came back to upset fourth- seeded Frenchwoman Alize Cornet 3-6, 6-0, 6-3 and French journeywoman Virginie Razzano doused wild card and former French Open champion Francesca Schiavone of Italy 6-2, 6-3. Cornet titled here in 2013 and was the Strasbourg runner-up in 2012. Schiavone was the 2012 champ.

The other quarterfinals will pit second-seeded former world No. 1 Jelena Jankovic against American Sloane Stephens, third-seeded former U.S. Open champ Samantha Stosur versus Croat Ajla Tomljanovic and Vesnina against the wild card Razzano.