Spanish second seed Rafael Nadal responded to the challenge thrown down by 2014 champion Marin Cilic as he battled to reach the US Open quarter-finals with a four-set win.
Nadal, 33, ultimately had too much quality for the Croatian 22nd seed in a 6-3 3-6 6-1 6-2 victory in New York.
Cilic, 30, briefly rediscovered his best form to level before wilting.
Nadal, the 18-time Grand Slam champion, will play Argentine 20th seed Diego Schwartzman in the last eight.
“For some moments in the second set I felt there were too many points in his hands, he was pushing me back, more aggression than me and he hit every ball very strong,” said Nadal.
“After that second set I thought something needs to change or I would be in his hands. I started to return the second serve inside the court and that created a different perspective.”
After 2018 champion Novak Djokovic retired injured from his last-16 match against Stan Wawrinka on Sunday, Nadal is considered the joint favourite for the men’s title alongside Swiss great Roger Federer.
Nadal is aiming to close the gap to 20-time major winner Federer with his fourth title at Flushing Meadows.
The illustrious pair remain on course to meet in Sunday’s final which, remarkably, would be the first meeting in New York of their enduring rivalry.
First Nadal must see off Schwartzman, who reached the last eight for the second time by beating German sixth seed Alexander Zverev.
Golf great Tiger Woods, who was animatedly supporting Nadal throughout, leapt to his feet as Ashe rose to acclaim the sheer brilliance of the Spaniard.
Federer, 38, plays his quarter-final against Bulgaria’s Grigor Dimitrov at about 02:00 BST on Wednesday.