Top seed Dominic Thiem threw away the lead as he was dumped out of the quarter-finals by Dan Evans at the Sydney International on Thursday, the Briton winning 3-6 6-4 6-1.
For world number 67 Evans it was a maiden victory over top-10 opposition, overcoming the Austrian in two hours and two minutes to set up a last-four clash with Andrey Kuznetsov, who also came from a set down to see off Pablo Carreno Busta.
Two-time defending champion Viktor Troicki progresses thanks to the withdrawal of Philipp Kohlschreiber due to a back injury, with Gilles Muller - 7-6 (7-5) 6-4 winner against Pablo Cuevas - his last-four opponent.
"[Troicki] hasn't lost a match in Sydney in, like, forever," said Muller.
"He beat me in the semis two years ago. I know he's a great player - he's up there for a long time and it's going to be a tough match.
"For me it's the third year in a row for the semi-finals, so I'd also like to get one stage further. I think I'd be more happy with that than ending his winning streak."
-- British Tennis (@BritishTennis) January 12, 2017
At the ASB Classic, Steve Johnson won 85 per cent of his first serve points to get the better of countryman and second seed John Isner 6-3 5-7 7-6 (7-3).
Johnson heads into another all-American clash in the semi-finals, with Jack Sock having bounced back from losing the first-set to eliminate Jeremy Chardy in a 5-7 6-4 6-3 victory.
The other last-four match in Auckland will see Marcos Baghdatis take on Joao Sousa following respective wins against Jiri Vesely and Robin Haase.