2016 Auckland champion Roberto Bautista Agut regained his crown after a 6-1 4-6 7-5 victory against the second seed Juan Martin del Potro in 2 hours and 7 minutes, claiming his 7th ATP title in a career.
The Spaniard would defeat the 2009 US Open victor 6-1, 4-6, 7-5 in a touch over two hours on the hard courts of Auckland in New Zealand.
Del Potro had said beforehand he expected Bautista Agut would target his inconsistent backhand, but the Spaniard was also prepared to attack the forehand court when the opportunity presented itself.
The second-seeded del Potro - a red-hot favourite for Saturday's Auckland final - fell 6-1 4-6 7-5 to his Spanish opponent, failing to fire early.
The battle of the service games continued in the third, with Bautista Agut finally breaking through to go 6-5 up after which he saved a break point and served out the match for his second ASB Classic title.
"I'm exhausted", Del Potro said in a court-side interview.
Del Potro beat Russian Karen Khachanov 7-6 (7/4), 6-3 in his quarter-final.
"I started the match very well".
"Roberto played solid in the last two games of the match - that was key". I think I played very aggressive...
"I have been fighting all week and felt like I wasn't playing good tennis but today I did". Juan Martin netted a backhand to get broken in game number 2 but he fired up his mighty forehand to get back on the track in the following game, breaking back with a volley victor and reducing the deficit to 2-1.
"Today the conditions were hard and he was a hard opponent, serving very well and a lefty, playing with a very flat backhand", Bautista Agut said. "But then my game improved a little bit and I made mistakes in the last game", del Potro said.