Rafael Nadal fully welcomed himself back to Flushing Wednesday night.

After having his first-round U.S. Open match cut short because of his opponent’s injury, the defending champ wasted no time breezing past Canadian Vasek Pospisill 6-3, 6-4, 6-2 to finish off the action at Arthur Ashe Stadium.

The No. 1 player in the world and the tournament’s top seed advanced to Friday’s third round, where he will face No. 27-seed Karen Khachanov.

“He just is relentless,” Pospisill said. “I played Rafa once before [in the 2015 China Open]. It was nothing like this.”

Pospisil made a brief charge at an upset in the second set, which he led 4-2. But Nadal stormed back to shut those ideas down, taking the next eight points and 16 of 17 to win the set on the way to the sweep.

About the only bump in the road for Nadal came in the third set, when the umpire gave him a warning for the shot clock — which was implemented in July — expiring as he tried to give Pospisill a few extra seconds to breathe.

“The thing for me was very clear. I was ready to serve, and he was doing me like this,” Nadal said, holding his hand up. “He had to breathe or he was cramping.”