Ahead of the last eight showdown at Flushing Meadows, Nadal had described "close friend" Schwartzman as "one of the best talents on the men's tour," but he was at his ruthless best against the tournament's 20th seed on the Arthur Ashe court in New York.
Schwartzman, 27, had enjoyed an impressive run-up to the last eight stage of the grand slam, including an eye-catching four-set victory over sixth seeded Alexander Zverev of Germany.
But Nadal was on another level in the opening set as he raced into a 4-0 lead. Schwartzman rallied back superbly, to his credit, to level the match at 4-4 - with four straight games of his own.
Eyeing a 19th grand slam, Nadal knew he was up against a tough opponent, who created two break points for a 5-4 lead before the Spaniard dug deep to hold and clinch the opener with another break.
There was a similar pattern in the second set, as Nadal raced into a 5-1 advantage, only for Schwartzman to bounce back at square things up at five games all. But Nadal showed his quality by breaking serve in the 12th game of the set, winning on his third set point.
Nadal wrapped up the third and final set of an enthralling contest more comfortably - taking it 6-2 - securing victory in two hours and 46 minutes, before he warmly embraced the Argentinian at the net.
