Alexander Zverev knocks over Tommy Paul in return to Australian Open semis

• No 2 seed books spot in last four with four-set win
• German will now face Djokovic in semi-finals

Alexander Zverev has survived an extraordinary meltdown to sink Tommy Paul in four sets and charge into the Australian Open semi-finals.

Second-seeded Zverev, chasing an elusive grand slam title, was almost knocked down by, of all things, a feather before he steadied to prevail 7-6 (1), 7-6 (0), 2-6, 6-1. Zverev will next face 10-time champion Novak Djokovic in his third Melbourne Park semi-final.