Indianapolis Colts coach Chuck Pagano has admitted that his side made too many errors during their pre-season match against the Buffalo Bills on Sunday.

The Colts fell to a comprehensive 44-20 loss in their opening warm-up match, prompting franchise owner Jim Irsay to criticise his side's performance.

The match was littered with errors in both attack and defence for the Colts, and Pagano believes that the problem was partly due to mental errors as well as the obvious physical ones.

"I think probably a combination of [mental and physical errors]," Pagano told reporters on Monday.

"You get a lot of young guys out there. I don't mean it as an excuse but we made some mental errors and then, give [Buffalo] credit, they did a nice job and put some heat on us, put some pressure on us and some things like that."

The Colts will face the New York Giants in their next pre-season match on Sunday.