She lit up the WTA Tour as a teen in the late 1990s until she was overwhelmed by family and financial problems. Last month at Strasbourg, Lucic reached her first quarterfinal since 1999.
Also, Daniela Hantuchova defeated Alla Kudryavtseva 6-4, 6-2. She will face American Alison Riske, who defeated Aravane Rezai 7-5, 6-7 (6), 6-2. Peng Shuai of China, who was in the top 20 for the first time, stopped Heather Watson of Britain 7-6 (1), 6-1.
At 15, Lucic became the first player to win her first WTA singles event in 1997 at Bol, Croatia. She was the youngest Australian Open champion by pairing with Martina Hingis (1998).
At 17, she was a Wimbledon semifinalist. But her life unraveled and she escaped her abusive Croatian father and coach. She began a serious comeback last year and is currently ranked 94th, her highest ranking since July 2000.
In the second set Thursday down 6-5, there was a rain delay as Lucic was about to serve to save the set.
"Luckily, I was able to slow down," Lucic said. "I told myself if I rushed I would lose the point, and I was able to make myself stay in the moment."