Spaniard Roberto Bautista Agut has cruised into the ASB Classic semi-finals with a 7-6 (7-1) 6-2 win over Czech Jiri Vesely.
In a battle between the 2016 Classic champion and the 2015 Classic champion, the more recent Auckland victor ultimately proved too strong.
The fifth-seeded 29-year-old earned an early first-set break before holding off a Vesely fightback to boss the tiebreak and win the set.
He then blitzed the second set, unleashing his trademark ground-stroke game and playing relentlessly accurate shots to settle the match.
He also won more than 60 per cent of Vesely's second-serve points, demonstrating the big Czech's reliance on his powerful first serve.
Bautista Agut, the world No.21 and first-round vanquisher of Kiwi Michael Venus, will go on to face Robin Haase in Friday's semi-final after the Dutchman defeated giant-killing German Peter Gojowczyk 6-4 6-4.
A potential final against Juan Martin del Potro may then await.
"Today the conditions were difficult and he was a difficult opponent, serving very well and a lefty, playing with a very flat backhand," Bautista Agut said.
"It was tough at the beginning, to have rhythm with the ball.
"I served really well in the second set and I tried to play aggressively with my forehand, and I think I did it."
He had also beaten Steve Johnson in three sets in Wednesday's second round.
In Thursday afternoon's later game, Spanish veteran David Ferrer dismantled Korean young gun Hyeon Chung 6-3 6-2 in 75 minutes.
He'll face either del Potro or Karen Khachanov in his semi-final.