Australian men's No.1 Bernard Tomic's quarter-final against Russian Teymuraz Gabashvili at the rain-affected Sydney International has been postponed until Friday morning.
Former Wimbledon semi-finalist Grigor Dimitrov will also have to wait until Friday to try to book a place in the final four.
Dimitrov, the world No.28, led Ukraine's Alexandr Dolgopolov 4-6 6-3 4-2 when rain suspended play on Thursday afternoon for a second time.
While tournament organisers still hope to play both women's semi-finals on Ken Rosewall arena on Thursday night, the men's side of the draw has been held up until Friday morning.
A frustrated Dimitrov had dropped the first set against Dolgopolov when a heavy storm caused a 90-minute delay, but the Bulgarian returned a different man on resumption, dominating on serve to force a third set.
The fourth seed carried his momentum into the decider and needed just two more games to claim a semi-final berth, only to be forced back into the locker rooms by more showers.
The winner of the Dimitrov-Dolgopolov match will play Frenchman Jeremy Chardy or Luxembourg's Gilles Muller, who trailed Chardy 7-6 (7-5) when rain halted proceedings.
In the fourth quarter-final, Serbia's Viktor Troicki and French qualifier Nicolas Mahut were locked at 2-2 in the first set.
