DALLAS — Reilly Opelka faces potential discipline for his postmatch comments about a chair umpire he called the “worst ump on tour,” the ATP said in a statement Friday.

Opelka was angered that he received a point penalty while serving for the match in the third set against Cameron Norrie at the Dallas Open on Thursday night. Opelka went on to win 4-6, 7-6 (5), 6-4.

The 27-year-old American was penalized for using profanity while berating a member of the crowd. Opelka said the unidentified fan was repeatedly and intentionally disrupting his serve.

“Audible obscenities directed at members of the public constitute a clear violation of ATP rules,” the tour said in its statement. “In such instances, the chair umpire has a responsibility to take appropriate action, regardless of the match score. The ATP will review Mr. Opelka’s post-match comments as part of its standard disciplinary process.”

After the match, Opelka said umpire Greg Allensworth failed to stop the fan from disrupting play.

“Worst ump on tour,” Opelka said. “He’s real bad. Almost changed the outcome of that match just because he doesn’t really know what he’s doing. And he got emotional when we were arguing. … He didn’t tell [the fan] to shut up? He was doing it for, like, three points. He didn’t do his job, so I had to tell him, ‘Get out of here.'”