Updated

Police are investigating an assault complaint filed against David Nalbandian after the Argentine tennis player kicked an advertising board and injured a line judge during the Queen's Club final.

London police declined to say who made the complaint against Nalbandian, who was defaulted from Sunday's match against Marin Cilic in the grass-court Wimbledon warmup event.

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 on Monday. "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.

Tournament director Chris Kermode said McDougall received first-aid care but needed no further treatment after seeing a doctor.

Nalbandian was disqualified for unsportsmanlike conduct. ATP rules state that any violent action will result in an automatic default.

Nalbandian also was stripped of his $57,350 in prize money and could face a fine. He is still scheduled to play at Wimbledon, which starts Monday.

Nalbandian insisted he shouldn't have been disqualified.

"It's very tough to end a final like that," he said.