The No.4 seed attacked Marozsan's serve and converted three of his seven break-point chances, swatted aside the two break points he faced and won 80 per cent of his first serve points en route to the last four in Miami where he has yet to drop a set.

Despite not dropping a set in windy conditions, Zverev had his hands full with Marozsan, who is making his Miami debut and enjoyed top-10 upsets over Holger Rune and Australian Alex de Minaur on the way to the quarter-finals.

"If he continues playing like that he's going to rise up the rankings very quickly and he's going to be one of those (top 10) guys himself," Zverev said in his on-court interview.

"When we are in control, I think all top players when they are in control they feel like they can manage the match, manipulate the match a little bit in their own favour.

"But against him that's not possible. That's why he has such a great top-10 record and he's an unbelievable player."

Zverev's win, sealed with a break when he unleashed a brilliant backhand down the line, marked his return to the Miami Open semi-finals for the first time since his runner-up finish in 2018.

Zverev will next face either Spanish top seed Carlos Alcaraz or Bulgarian 11th seed Grigor Dimitrov.

Australian Associated Press