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.
In addition to forfeiting his prize money (around £35,000) and ranking points, Nalbandian has been fined the maximum 10,000 euros by the ATP for the incident.
A Scotland Yard spokesman 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 per cent. 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."
