'I finally defend!' World No. 2 Karolina Pliskova powers to victory to retain Brisbane Open title (VIDEO)

The second-ranked player in women's tennis, Karolina Pliskova, followed up on her epic semi-final win over Naomi Osaka by defeating American Madison Keys 6-4, 4-6, 7-5 to successfully defend her Brisbane Open title on Sunday.

Pliskova battled on court for almost three hours against Osaka on Saturday, and some were concerned about how much gas was left in the tank for the final the following day.

But Pliskova maintained her impressive pace and, working off the back of her big serve, took an early lead, saving two break points before converting her first on Keys' serve to take the first set 6-4.

But it wasn't plain sailing for Pliskova, and Keys fought back strongly in the second set, fighting back from an early break to break Pliskova twice and take the second set 6-4.

The deciding set saw each of the first six game go with serve ass the tension increased throughout the final frame. Then, in the seventh game of the set, Pliskova made what looked like the matchwinning breakthrough when she broke Keys' serve. But Keys broke straight back to save the match with the score at 5-4.

But Pliskova maintained her focus and broke Keys again in the very next game to give her the opportunity to serve out the match, and the tournament, 7-5 as she recorded the first title defense of her career.

"I think what’s more special than winning is that I finally defend (a title)," said Pliskova after the match.

"That’s always harder. But, yeah, it took me a couple of years to do it, but pleased with that."

Pliskova's 42 aces in the tournament not only helped power her to success in the tournament, they also earned $8,400 towards the Australian bushfire relief fund.