Radwanska, who had breezed into the title match by losing only 11 games over four matches, edged past Pavlyuchenkova 6-7 (6-8), 6-3, 6-4 in a battle that took 2 hours 45 minutes to complete.
Radwanska dropped serve twice in the seesaw first set and failed to convert four set points before losing the tiebreaker that finished the set, which took more than an hour to decide.
She came back with three breaks in the second set to even the match. She fought off four break points before getting the only break of the third set for a 5-4 lead that allowed her to serve out for the win.
It was the 13th WTA title of Radwanska's career, which is tied for sixth most among active players. She won two tournaments in January and has one other finals appearance this year. She is the fourth player with at least three championships in 2013. No. 1-ranked Serene Williams has nine, Simona Halep won four from June-August and second-ranked Victoria Azarenka has three wins.
Pavlyuchenkova, who was appearing in her fourth final of 2013, fell to 5-3 in title matches overall. Two of the championships have come this year.
The $112,000 first-place check pushed Radwanska's career winnings to more than $13.2 million. Pavlyuchenkova collected $56,000 as the runner-up and has won more than $3.6 million in her career.