Tsitsipas lost out on the chance to claim the title of world No. 1 after an epic showdown in Louis Armstrong Stadium, where world No. 94 Galán took the victory on his ninth match point.
Winning only seven points in the opening set, Tsitsipas lost the first 11 games to the Colombian before picking up his play and winning the third set.
“I think he started playing better in the third set. He served much better than the first two and I was putting the serve in the court but not putting pressure on him. He was always in control,” Galán said.
“I think he felt really comfortable during those two sets. I tried to change a little bit the position when I was returning and that was a change a lot because I was able to return [deeper] and he was not so offensive on the first ball, so I was able to do a little bit more.”
Though Tsitsipas fought hard in the fourth, he was unable to hold the Colombian off, with Galán taking the set and match.
“He dominated the match,” Tsitsipas said after the event. “I just couldn’t get into it.”
Meanwhile, Galán said his US Open main draw debut was “definitely the best match of my career, not only because of the circumstances, also the opponent. I’m really happy.”
Galán will take on Australian Jordan Thompson next.