Down 2-0 in the second set of her second round match against No.2 seed Julia Goerges, Hercog reeled off six straight games en route to a 76(4) 62 triumph. She is now 2-2 against the German, victorious in both of their meetings on clay but falling in their two encounters on hardcourts.
Hercog came into this week on a five-match losing streak but seems to have rediscovered the form that took her to her one and only WTA title here last year.
"I'm just really happy to get this victory," Hercog said. "She was not an easy opponent, so it's great for me to get through this match, especially after the tough time that I had yesterday. I'm trying to get better with every match."
Down 4-3 on serve in the first set, Pavlyuchenkova won nine straight games for a 64 60 defeat of Sílvia Soler-Espinosa, putting her into her second quarterfinal of the year after Eastbourne.
"I was maybe a little bit lucky in the first set," Pavlyuchenkova said. "And then in the second she went down a level and I raised my level and got into a rhythm. She's not an easy player, especially on clay. It's definitely her favorite surface. I'm happy that I had a solid match and got through in straight sets."
Barthel, who came into this week on a six-match losing streak, was a 62 75 winner over Kateryna Bondarenko.
In first round action, Swedish crowd favorite Larsson rallied from a set point down in the first set tie-break and was up a break in the second when opponent Olga Govortsova retired at 76(6) 43 due to a viral illness.
"It was very difficult out there with the wind and the cold weather, but I'm very happy to get through," Larsson said. "It's nice that everyone's so positive and happy that I'm back here. I have very good memories from last year."
Larsson squares off against clay court specialist Anabel Medina Garrigues in one of Thursday's featured matches.