Rafael Nadal believes now is the moment to step up the defence of his US Open title after another tough battle against Nikoloz Basilashvili.
After battling for nearly four and a half hours to beat Karen Khachanov on Friday, Nadal was again pushed beyond the three-hour mark before defeating his Georgian opponent 6-3 6-3 6-7 (6/8) 6-4.
Basilashvili, ranked 37, had won just a single game against Nadal in their only previous meeting at the French Open last year but played superbly here, especially in the third-set tie-break.
Next up for Nadal is a quarter-final against ninth seed Dominic Thiem, who is the only player to beat him on clay for the last two seasons and who ended the run of last year's beaten finalist Kevin Anderson on Sunday.
Nadal defeated Thiem in the French Open final but has a lot of respect for the Austrian. This will be their first meeting on hard courts after 10 matches on clay.
"He's a fantastic player," said Nadal. "He's a very powerful player. He's a great guy. I have a very good relationship with him.
"It's going to be a tough one. He knows how to play these kind of matches. I need to play my best match of the tournament if I want to keep having chances to stay in the tournament.
"Now is the moment to make the next step, step forward, play more aggressive. I did a lot of things well during the whole season. It's the moment to make it happen again. I hope to be ready to make that happen."