De Minaur, who was fresh off an upset over second seed Daniil Medvedev, delivered a simple gameplan in rather tricky conditions while Davidovich Fokina struggled to find any sort of rhythm throughout the 78-minute match.

"First thing I knew once I stepped out on court it wasn't going to be pretty so I didn't expect perfect tennis from my side of the court today," said De Minaur, who wrote "so windy" on an on-court camera lens after the match.

"I just told myself to stay positive, keep competing no matter what and you never know what's going to happen.

"So I thought I had a great mindset today ... didn't play the best of tennis but I did what needed to be done today in these conditions."

Up next for De Minaur, who until this week had never before reached the quarter-finals of a Masters 1000 event, will be a clash with either Italian seventh-seed Jannik Sinner or 12th-seeded American Tommy Paul.

De Minaur wasted no time setting the tone against Davidovich Fokina as he broke the Spaniard twice en route to a 5-1 lead before serving out the opening set on his first opportunity.

The Australian maintained the pressure as he broke Davidovich Fokina four times to build a 5-2 lead in the second before sealing the match with his seventh break.

"I've had a hell of a week. It's been the breakthrough that I always knew I had inside of me so it's great to show it and play for a final," said De Minaur.