Roger Federer came through a demanding quarter-final with Grigor Dimitrov to book his place in the last four of the Brisbane International on Friday.

Defending champion Federer was taken to three sets by the world number 28 and spurned three match points after getting to 0-40 when his opponent served at 3-5 in the decider.

Dimitrov reeled off five points in a row to keep his hopes alive, but the top seed held to love in the next game to complete a 6-4 6-7 (4-7) 6-4 triumph.

Federer will now face Dominic Thiem, who came from a set down to also prevail 6-4 in a third set against Marin Cilic.

After his victory, Thiem said: "Today was a big test for me so I'm happy with the win. I hope Federer wins so I play him next."

And his wish was granted as the 17-time grand slam champion recovered from losing a second-set tie-break to keep his title defence on track.

In the bottom half of the draw, Bernard Tomic sprung a shock by recording a first career victory over second seed Kei Nishikori, the Australian prevailing 6-3 1-6 6-3 in a topsy-turvy encounter.

Tomic lost to Nishikori at the same stage of last year's tournament and was delighted to avenge that defeat.

"Obviously I had the opportunity to play him last year and [it] was a different level for me today," said Tomic. "I've improved so much."

"This win is huge. I needed match wins against these high profile players around the world."

Tomic will face Milos Raonic in the last four after the Canadian dropped just two points on his first serve in a 6-4 6-4 win over Lucas Pouille.