Christian Pulisic Does Worm Dance Goal Celebration to Honor Fan Battling Cancer

U.S. men's soccer star Christian Pulisic gave a touching shout-out to a fan battling cancer during Sunday's game -- by fulfilling his request and doing the worm dance on the field right after scoring!!

The moment happened during USMNT's 5-1 win over Panama in World Cup qualifying on Sunday ... with the 23-year-old midfielder hitting the grass after scoring his second goal -- and busting out the iconic "worm" dance.

"Look at this," the FS1 broadcaster said as Pulisic executed the 1970s move.

"Okay!! Busting out the worm!"

As it turns out, Pulisic's reasoning behind the throwback celly will tug at your heartstrings -- the star says he did it as a promise to a fan named Mason Ogle, a 15-year-old high school soccer player who was diagnosed with bone cancer.

The two met during Saturday's workout ... which Pulisic mentioned after the game ... saying, "I met someone really special yesterday."

"His name was Mason, and his one request was that if I scored, he wanted to see a worm celebration," he said.

"That’s what that was for."