Trinity Rodman Roasts Boyfriend Ben Shelton With Question At US Open

Ben Shelton's toughest moment from the US Open didn't come from one of his opponents on the court ... but from his girlfriend during a postgame media session -- 'cause Trinity Rodman snuck in a savage question about his "slow" serves!!

Shelton met with the media after he advanced to the third round with a win over Spain's Pablo Carreño Busta in straight sets. Just as he was about to wrap up his day, Rodman -- who was present for the Q&A -- was able to ask one last question, much to her man's surprise.

"So, how did it feel not being able to serve faster than 135 today," she asked. "I just know you like to serve big, and it wasn't breaking 140 today."

He asked the media relations person how Rodman ended up with the microphone ... to which he replied, "My orders from the boss over there."

After getting some laughs out ... he went on to answer the question honestly.

"It was cold outside," Shelton said. "So I think that was the main reason. I was focused on hitting spots, and I didn't hit those spots. So maybe I should just serve bigger, something that I'll definitely work on next time."

A wholesome moment from these two lovebirds, who began dating earlier this year. Rodman -- a member of the NWSL's Washington Spirit -- had been dropping hints about the two before Shelton made it official when he hard-launched them on his social media page.

Unclear how much longer Rodman will be in town ... as the Spirit have a home match this Sunday against Chicago Stars FC. Shelton's next contest is Friday, so it might be a tough turnaround for the 23-year-old soccer star to stay in the Big Apple.