Argentine tennis star Juan Martin del Potro has set up a blockbuster Auckland Classic semi-final against Spanish veteran David Ferrer, beating prodigious Russian Karen Khachanov in straight sets.
The 29-year-old del Potro, an ex-US Open champion and the 2009 Classic victor, will face another ex-champion in Ferrer.
A potential final against Juan Martin del Potro awaits.
Second-seeded del Potro, champion in 2009, beat four-time champion and eight-time semifinalist David Ferrer 6-4, 6-4 in just under two hours while Bautista Agut, the 2016 champion, beat Robin Haase 6-7 (7), 7-6 (3), 7-6 (5) in a three hour marathon.
Ferrer, who has won the tournament four times, broke his opponents serve five times (twice in the first set and three times in the second) and was always in control.
In Sydney, 18-year-old Alex de Minaur continued to delight the home crowd with a 6-4 6-4 win against Feliciano Lopez and will face Benoit Paire in the semi-finals, after the Frenchman knocked out defending champion Gilles Muller.
Del Potro - who'll head into the final as a red-hot favourite - hoped to lift the trophy once again, as he gears up for a 2018 Australian Open tilt.
Bautista Agut coasted into Friday's semi-finals with a 7-6 (7-1) 6-2 win over Czech Jiri Vesely, while Haase trumped giant-killing German Peter Gojowczyk. "I didn't expect to play at this level in the first match of the year".
"I tried to not make mistakes, play in the right places, try and play as hard as possible with all the pressure", Bautista Agut said of the third-set tiebreak.
"We've played many matches on tour - his forehand is pretty good, serves are good and returns so well, so I must be smart", the world No.12 del Potro said.
"If he has a good day, he is very unsafe as a lefty, he serves well and volleys".