David Nalbandian was fined the maximum $12,560 and placed under police investigation for assault after kicking an advertising board and injuring a line judge during the Queen's Club final.
The ATP confirmed the fine for unsportsmanlike conduct on Monday and said the Argentine player also was stripped of his 36,500 pounds ($57,350) in prize money.
London police, meanwhile, said they were investigating a complaint of assault filed against Nalbandian, who was defaulted from Sunday's match against Marin Cilic in the grasscourt Wimbledon warmup event.
Police declined to say who made the complaint. Any member of the public who witnessed the event in person or on television could have made a complaint, as could the line judge himself.
"We are aware of an incident at the Aegon Championships," the Metropolitan Police said in a statement. "A complaint has been made and the Metropolitan Police Service is now investigating. The allegation is of assault."
Nalbandian won the first set 7-6 (3) but lost his temper after losing serve to fall behind 3-4 in the second. After missing a running forehand on game point, he kicked the board under the chair of line judge Andrew McDougall. A piece of the board cut the judge on the left shin, leaving him bloodied from an inch-long gash.
Nalbandian was disqualified for unsportsmanlike conduct. ATP rules state that any violent action will result in an automatic default.
Nalbandian, who is still scheduled to play at Wimbledon when it starts on Monday, insisted he shouldn't have been disqualified.
"Sometimes you get very frustrated on court and it's tough to control that, and sometimes I do a mistake. So it's very tough to end a final like that," he said. "I agree I do a mistake but sometimes everybody do a mistake and I didn't feel it had to end like that, especially in a final."
ATP rules state that any violent action will result in an automatic default.
"He's actually quite seriously injured," tournament director Chris Kermode said. "Rules are rules. The ATP have forced us to end the final with a code violation."
Kermode said the unidentified line judge had been taken to the medical center.
"It's definitely not the way I wanted to win it," Cilic said. "The match was still open but I can't change it. I'm sorry for the (spectators) that it had to end like this.
"We had some good rallies, and it's hard to see the final end like this."
The Argentine had been leading the sixth-seeded Cilic 7-6 (3), 3-4 in the grass-court Wimbledon warmup when the incident occurred.
"There is a lot of rules, and sometimes they (ATP officials) don't do anything. The rule book is very big and I can tell you that the ATP do a lot of mistakes to the players and nothing happens," Nalbandian said.
Nalbandian was playing his first final on grass since losing to Lleyton Hewitt at Wimbledon 10 years ago. He was bidding to become the first player from Argentina to capture an ATP grass court title since Javier Frana won at Nottingham in 1995.
Nalbandian's last title came in Washington in August 2010.
"We have a sold-out crowd. It's packed. We were watching some great tennis so to have the match end this way is incredibly disappointing. In sport, these things happen. There's not a lot we can do about it. We are under the governorship of ATP rules and that's how it stands," Kermode said. "It's a great crowd, great final. You'd like to think you can bend it, but I can see from their point of view it's difficult."