Goals from Henrik Ojamaa and Michael Higdon and a Fraser Forster own goal saw the Steelmen claim back-to-back victories over the Hoops, who had taken the lead through Gary Hooper.
McCall told the club's official website: "I'm delighted and proud for all the staff, players and everyone connected to the club.
"To put in a performance like that, especially after going a goal down to a team like Celtic, was brilliant. It was a good open day with some great performances and it's a day we've got to cherish.
"The players covered the ground, got around the park, got into players and I thought the desire and hunger was terrific but I also thought some of the football was outstanding.
"It was a combination of good play from goalkeeper to attackers and it was a joy to watch."