Top seed Rafael Nadal has set up an intriguing U.S. Open quarter-final showdown with Dominic Thiem after snuffing out a comeback attempt by Georgia's Nikoloz Basilashvili with a 6-3 6-3 6- 6-4 win.
The world number one looked like he would cruise to an easy win after pocketing the first two sets but the Georgian stepped up his game to take the third.
The U.S. Open champion would not be denied, however, and fired his seventh ace on match point to end the three hour, 20-minute tussle.
"Two matches in the row that were very tough ones," said Nadal, who had to battle back against Russian Karen Khachanov two days ago.
Nadal praised the 26-year-old Basilashvili, who will break into the top 30 for the first time when the new 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," the Spaniard said.
Nadal said he will need to raise his game to get past the red-hot Thiem, who reached his first U.S. Open quarter-final when he defeated 2017 U.S. Open runner-up Kevin Anderson in straight sets.
Meanwhile Serena Williams survived a scare from giant-killer Kaia Kanepi to claim a rollercoaster 6-0 4-6 6-3 and also move into the final eight taking her a step closer to a record- equalling 24th career Grand Slam title.
Following a shock upset of world number one Simona Halep in the first round, the 44th-ranked Kanepi had looked a potential trouble spot for the six-times U.S. Open champion.
Any tension inside a packed Arthur Ashe Stadium, however, was quickly eased as a ruthless Williams stormed through the opening set in 18 minutes for the loss of a measly six points.
But in a bizarre twist in momentum, fans suddenly found themselves back on the edge of their seats as the Estonian opened the second with a break and broke Williams again to go up 5-2 before holding off a late rally from the 17th seed to level the match.
Having collected her first set off of Williams in five career meetings, however, there would not be a second.
Just as quickly as the momentum had swung to Kanepi in the second set it returned to Williams in the third as normal service resumed with the 36-year-old American breaking her opponent at the first opportunity and jumping out to a 3-0 lead before cruising into the quarter finals.