Dimitrov, seeded 15th, won 6-3 6-2 6-4 to reach his second major semi-final - the 25-year-old made it to the same stage at Wimbledon in 2014.
He next plays the winner of the match between Rafael Nadal and Milos Raonic, which gets under way at 08:30 GMT.
Roger Federer will play Stan Wawrinka in the first semi-final on Thursday.
Dimitrov, who works with Dani Vallverdu, former coach of Andy Murray and Tomas Berdych, began the year with a title in Brisbane and has won 10 matches in a row.
"The last two years have been a rollercoaster for me, but I'm happy with the way it happened," he said.
"I'm appreciating things much better now. To be back in the semi-finals of a Slam means too much for me right now."
Bulgaria's Grigor Dimitrov remains unbeaten in 2017 after beating Belgian 11th seed David Goffin to reach the semi-finals of the Australian Open.