Strathclyde police and Celtic have played down a complaint relating to the gesture made by Neil Lennon at the end of Sunday's Old Firm derby. The police indicated they would not be following up the complaint as officers witnessed the Celtic manager's gesture – cupping his ears as he left the field – and did not take any action at the time.

A spokeswoman said: "We can confirm we have received a complaint regarding Neil Lennon at the end of the Rangers-Celtic match. Strathclyde police officers were in attendance at the time and would have taken action at that time if they had deemed it appropriate."

The Celtic chief executive, Peter Lawwell, said: "It is absolute nonsense. It is laughable that such a ludicrous complaint has been made given the abuse Neil received throughout the match. It tells you more about those making the complaint than it does about Neil."

When the gesture was mentioned after the game, Lennon said: "Don't ask me about that. It's called humour, all right? Don't distract from my team's performance. Don't even write about it. You have the photographs, I'm sure, but it is just a bit of fun. I don't want to distract from my team's performance."

Nine arrests were made at the game but none of them was linked to sectarianism, police said. Six arrests were made in the ground, with another three immediately outside. Strathclyde police said all arrests were for "minor offences" such as being drunk inside the stadium and breach of the peace.

Police had predicted a surge in violence over the weekend and an extra 1,000 officers were deployed. Tension rose after it was revealed last week that parcel bombs had been sent to Lennon. Speaking before the 0-0 draw, Lennon said the threats would not stop him from managing the Parkhead club. "I've had this for 10 years but I don't want to say you get used to it, because you never do," he said. "But it is not going to deter me from doing what I want to do."

Two men were arrested on Sunday following police raids targeting the homes of people allegedly involved in Old Firm internet hate campaigns. A 23-year-old and a 27-year-old were charged with sectarian breach of the peace and are expected to appear in court on Tuesday.