World number three Grigor Dimitrov saved two match points as he outlasted Australian wildcard John Millman in the second round of the Brisbane International on Thursday.

Playing his first match of the tournament after having a first round bye, Dimitrov took just over two-and-a-half hours to subdue the gallant Millman 4-6, 7-6 (10/8), 6-3.

The defending champion will now play rising British star Kyle Edmund, who earlier beat 18-year-old Korean Chung Hyeon 7-6 (7/3), 5-7, 6-4.

Dimitrov has not played a competitive match in more than a month and he looked rusty against Millman, who was playing in front of his home crowd.

The Brisbane born and raised Millman has played some of his best tennis on the Pat Rafter Arena, and has taken sets off Roger Federer and Andy Murray in previous tournaments.

He looked like going one step further against Dimitrov when he brought up two match points in the tiebreaker, only for the Bulgarian to play some inspired tennis to save both.

"John played unbelievable tonight," Dimitrov said.

"He deserved to win tonight. He got a bit unlucky in the tiebreaker.

"I was just happy I kept good composure on the court, striking the ball well and fighting.

"Whatever I had today, I was happy I could win with it."

Dimitrov got an early break in the deciding set and held on to win, saying later the long match would be good for his Australian Open preparations.

"The first match of the year and I get to play two-and-a-half hours," he said.

"I was prepared physically and mentally."

On a day when Johanna Konta withdrew from her quarter-final with injury and Andy Murray announced he would not be able to play the Australian Open, Edmund gave British tennis something to cheer about with his win over Chung.

The youngster recovered from losing the second set to overwhelm his Korean opponent in the third set.

"He got a lot of momentum at the end of the second, broke me twice pretty quickly," Edmund said.

"So it was a good third set. I made an effort to really try and step up the intensity and energy and put some pressure on him."

American Ryan Harrison downed Germany's Yannick Hanfmann 6-7 (5/7), 6-4, 6-2, while Denis Istomin of Uzbekistan was too strong for US player Jared Donaldson 7-6 (7/5), 6-2.