Police have arrested a Swindon Town fan after he appeared to punch Leyton Orient goalkeeper Jamie Jones.
Orient's 3-1 win at the County Ground was marred when a Swindon supporter ran on to the pitch and attacked the visitors' goalkeeper.
Orient manager, Russell Slade, said although his player was unhurt, he was left angry by the incident - which he described as the worst he had seen since becoming a manager.
Swindon chairman Jed McCrory said the club would be launching a review of the its safety measures.
"We will be speaking to the police with reference to their report next week," he told the Swindon Advertiser.
"We don't condone any actions where supporters come on to the pitch and, if found guilty, he will receive a ban.
"We apologise to Jamie Jones, the Leyton Orient board members and their supporters and will review the stewarding around the ground to make sure this doesn't happen again."
Wiltshire Police confirmed they had arrested a 26-year-old man in connection with the incident.
A force spokesman said: "He was arrested on suspicion of pitch invasion and remains in custody at Gablecross Police Station, Swindon, at this stage.
"Police inquiries are ongoing."