London - British police are investigating a complaint of assault after Argentine tennis player David Nalbandian injured a linesman in a petulant outburst during the final of the Queen's Club tournament at the weekend.

The governing body of men's tennis (ATP) said separately that they had fined the player the maximum of 10 000 euros. Nalbandian had already forfeited prize money and ranking points for the week.

The ATP also said he could face an additional fine or ban once the governing body has finished reviewing the incident.

Nalbandian was leading Sunday's match 7-6, 3-3 when he dropped serve in the seventh game and reacted by kicking out at a wooden advertising board which disintegrated on impact and slammed into official Andrew McDougall's left leg.

A shocked McDougall cried out and instantly clutched his shin. When he rolled up his trouser leg, blood could be seen seeping from the wound.

He received some on-court attention before being escorted off the ground to the club's medical centre.

After prolonged discussions between officials, umpire Fergus Murphy disqualified Nalbandian for “unsportsmanlike behaviour” and awarded the match to his Croatian opponent Marin Cilic.

A Scotland Yard spokesperson said on Monday: “An allegation of assault has been made to us relating to an incident at the tennis tournament and we are now investigating.”

Nalbandian apologised after the incident, saying: “I know (what) I did (is) a mistake, 100 percent. I feel very sorry for the guy. I didn't want to do that. But sometimes you get angry and you cannot control those moments.” - Reuters