Nadal was the overwhelming favourite for his US Open quarter-final against Schwartzman and got off to a fast start, taking a 4-0 lead.
But the Argentine swiftly got back in the first set, getting the double break back to bring the score back to 4-4.
That seemed to ignite the Arthur Ashe Stadium crowd in anticipation of a close fought match.
The noise in the arena soon began to rise, with Schwartzman’s support making their voices heard.
The roof being closed only helped the acoustics of the atmosphere.
But the closed roof also makes it increasingly humid for the players, and Nadal was clearly feeling the heat after Schwartzman levelled the first set.
As he made his back to his chair, Nadal was spotted going through his kit bag for a fresh towel to pat him down.
He couldn’t find one and had to make do with one already on his chair, but wanted to get the attention of one of the ballboys to get more towels for him at his chair.
“Please, two more towels,” he said.
“Two more towels.”
The world No 2 managed to regain his composure quickly in the first set though as he broke Schwartzman again at 5-4 to take a 1-0 lead.
A long break before the second set also worked its magic for Nadal as he came out firing in the second set, breaking at 2-1 before getting the double break at 4-1.