Radwanska, who won back-to-back tournaments in Australia at the start of the year but has struggled since, edged out her Russian opponent 6-7(6/8) 6-3 6-4 in two hours and 45 minutes.
"Especially after a great match, almost three hours of great tennis at a really high level, of course I'm very happy," Radwanska said on the WTA's official website.
"It was a very close match - tight sets, all of them - but I was just a little bit better in the important moments.
"And at the end of the third set I think I was playing a little bit more aggressively than she was, and I managed to win a couple more points than her in the end."
Top seed Radwanska led 3-0 in the opening set and had four set points in the 12th game although Pavlyuchenkova rallied gamely to force a tiebreak, which she won.
But Radwanska came storming back, once again winning the first three games of the next set and this time the Pole did not let her advantage slip away to take the match to a decider.
The crucial break of serve in the third set came in the 10th game as Radwanska wrapped up the 13th title of her career.
"It's tough losing this match after fighting so long and coming so close," Pavlyuchenkova, who was the third seed, said.
"It's difficult and frustrating, but in tennis you can be up then down and you lose some and you win some."