Melbourne (AFP) - Last year’s runner-up Alexander Zverev served his way into the Australian Open semi-finals on Tuesday as he crushed young American Learner Tien under a barrage of aces.

Zverev won 6-3, 6-7 (⁵⁄₇), 6-1, 7-6 (⁷⁄₃) and faces world number one Carlos Alcaraz or home hope Alex de Minaur for a place in the final in Melbourne.