Top seed Roger Federer beat Australian wildcard James Duckworth 6-0 6-1 in 39 minutes to reach the Brisbane International semi-finals.
The 33-year-old’s victory came just 24 hours after he struggled to see off world number 153 John Millman.
Federer, last year’s runner-up, will face fourth seed Bulgarian Dimitrov, who beat Martin Klizan 6-3 6-4.
“I’m happy I had a match like this after yesterday,” said Switzerland’s 17-time Grand Slam winner.
“I felt tired. This morning, I had muscle pain and all that stuff. So I’m very happy I got it done quickly today.”
Japan’s Kei Nishikori meets Milos Raonic in the other semi-final as players warm up for the Australian Open, which starts on 19 January.
Nishikori, the 2014 US Open runner-up, beat Bernard Tomic 6-0 6-4, while Raonic’s booming serve helped secure a 7-6 3-6 7-6 victory over Australian Sam Groth.
Dimitrov, a beaten Wimbledon semi-finalist alongside Raonic, set up the Federer encounter with a comfortable 6-3 6-4 success over Slovakian Martin Klizan.
Federer will be seeking his fifth Australian Open triumph in the 2015 tournament.