World number two Karolina Pliskova will defend her Brisbane International title after edging Naomi Osaka in an epic three-set semi-final at Pat Rafter Arena on Saturday.

Pliskova triumphed 6-7 (10/12), 7-6 (7/3), 6-2 win in a two hour, 48 minute marathon and will play eighth seed American Madison Keys in the decider.

She was forced to come from a set down, then save a match point at 5-6 in the second, before seeing off the reigning Australian Open champion.

The two are no strangers to long matches against each other - Osaka edged Pliskova 6-4 in the third in the Australian Open semi-finals on her way to the title.

But few could have expected a match of this quality and length in the first tournament of the year.

With both players serving exceptionally well, the first set almost inevitably went to a tiebreak, which Osaka clinched on her fifth set point.

The second set was a repeat of the first with few opportunities to break until Pliskova faltered at 5-5 to give Osaka the chance to serve for the match.

She came from 0-30 down to 40-30, but Pliskova rallied, saved match point and then broke Osaka to send the set to a tiebreak.

Osaka then saw the third set slip away with two service breaks.

"That was one of the best matches that I've played on this court," Pliskova said.