Thirteenth seed Sjeng Schalken was disqualified from his second round match at the Nasdaq-100 Open for verbally abusing the umpire.
The Dutchman lost his temper during his match with Guillermo Canas, which the Argentine was winning 6-1 3-0.
Schalken was given a warning after hitting a ball over the stands and his heated reaction, which included foul language, saw him disqualified.
The ATP will launch an investigation before deciding on further action.
Schalken has an exemplary disciplinary record and is normally mild-mannered on court, prompting Canas to express amazement at the Dutchman's behaviour.
"It was all very strange," said the Argentine, who now moves into the third round.
"I was very
surprised because I've known him for years and he is normally
such a quiet, nice guy on the court and off the court.
"I think he was bit unlucky with the umpire but he made a
mistake and I think he knew he had to pay."
Schalken will automatically forfeit his $10,950 prize money and will also have to pay his hotel bill, which would normally be paid by the tournament organisers.