There were some tricky moments - she lost her serve twice early in the second set - but the No.6-seeded Pavlyuchenkova broke five times herself to beat Svitolina in an hour and 22 minutes, 62 64.
"I think she was playing well from the first point," Pavlyuchenkova said. "She seemed very relaxed, which surprised me, because she probably feels a lot of pressure to play everyone here. But I thought she was fresh and played really well - it wasn't easy, but I'm happy I pulled it through today."
Pavlyuchenkova was playing her second round robin match of the week, having lost to Simona Halep in her first one on Tuesday - but the Russian didn't feel like she was playing badly in that match at all.
"I didn't play badly yesterday - I thought it was a good match, and I thought it was better than 3 and 3, really. And Simona's really on top of her game right now. So I was looking at today like another day, another challenge. Every match is very important here so I was really focused on playing my best."
Thursday will be a day off for Pavlyuchenkova, and then on Friday she will play Alizé Cornet to decide who will join Halep as one of the two qualifiers from Group Serdika - Halep has already qualified.
"It makes it easier because Alizé and I will both be in the same situation," Pavlyuchenkova said. "I have a day off tomorrow and will try and get ready, and hopefully I'll have the energy to play her."
Pavlyuchenkova has beaten Cornet in all three of their previous meetings, but none have been easy.
"I have to play aggressively and consistent too - it won't be easy playing her on this surface," the Russian said. "I'll try to find all the sources of energy in me and just leave it all out there."
Svitolina was the alternate in place of Maria Kirilenko, who had to withdraw due to a knee injury.
The Ukrainian, who conquered Baku in the summer and turned 19 years old last month, holds a special distinction - she is the only teenager to win a WTA title in the last 20 months (the last teenager to win a WTA title before Svitolina was Timea Babos, who won the Monterrey title in February 2012).