World No.1 Rafael Nadal has set up an intriguing quarter-final showdown with Dominic Thiem after snuffing out a comeback attempt by Georgia’s Nikoloz Basilashvili at the US Open.

The top-seeded Spaniard looked like he would cruise to an easy win on Sunday after pocketing the first two sets but the Georgian stepped up his game to take the third set.

The defending US Open champion would not be denied and fired his seventh ace on match point to end the three hour, 20-minute tussle 6-3 6-3 6-7 (6-8) 6-4.

“Two matches in the row that were very tough ones,” Nadal, who had to battle back against Russian Karen Khachanov two days ago, said.

Nadal praised the 26-year-old Basilashvili, who will break into the top 30 for the first time when the next rankings are released after the tournament.

“He played fantastic. A lot of credit to him. He was playing great, hitting the ball very, very strong,” he said.

“I’m very happy to be through,” Nadal said.

His next assignment is a rematch of June’s French Open final, in which he crushed Thiem in straight sets to win his 17th major.

The Austrian ninth seed booked his place in the last eight by eliminating last year’s runner-up Kevin Anderson 7-5 6-2 7-6 (7-2)

Thiem neutralised 203cm Anderson’s blistering serve by standing far beyond the baseline and he chased down everything the South African could throw at him.

He played a near flawless match, dropping just four points on his first serve and firing 42 winners.

“One of my best matches ever,” Thiem said of his dazzling performance in an on-court interview, calling his quarter-final berth “a dream coming true”.

Thiem told reporters that his positioning on the court inside the newly-built Louis Armstrong Stadium was critical.

“The court, I think, made a big difference. It’s a huge court,” Thiem said.

“I could go very far back like I do on clay usually. So there were some good advantages for me today.”

Meanwhile, John Isner ground out his third three-hour-plus match in a week by nailing critical break points to beat Canadian Milos Raonic 3-6 6-3 6-4 3-6 6-2.

The American 11th seed advanced to the quarter-finals of his home grand slam for the second time off the back of 56 winners and 20 aces.

“This crowd kept me in it – it was fantastic,” Isner said in an on-court interview.

“This is why us tennis players train so hard … to be in a match like this in front of a crowd like this.”

Isner will next play Croatian Borna Coric or third-seeded Argentine Juan Martin del Potro for a place in the semi-finals.