Goals from Connor McManus and Joe Thomson gave the Hoops victory at Murray Park in March to put Gordon Durie's side on the back foot in the race for the Under-20 league crown.
McMullan was one of the visitors' key men that day as he terrorised Gers defender Chris Hegarty, who was sent off in the closing stages of the game at Auchenhowie.
After hitting a superb run of form in recent weeks, Rangers make the trip to Lennoxtown this afternoon for the game that could see them lift the title.
While Stevie Frail's side need to win their final two games against their Old Firm rivals and Dundee United on Thursday, Rangers know a draw today will get them over the line and render the Arabs clash meaningless.
The stakes couldn't be higher as the Glasgow kids battle it out for the silverware.
But winger McMullan insists the Hoops are heading into the derby clash in high spirits.
"The Rangers game at Murray Park was probably the highlight over the past 12 months," the youngster told the official Celtic website.
"It was one of those nights where everything I tried came off.
"It's nice to have those games, and for it to be a big occasion against Rangers was great as well. The first couple of times I managed to get by the guy I was playing against.
"It worked well so they kept giving me the ball.
"Obviously the two goalscorers take a lot of credit, but it was good to contribute in such a big game.
"The way we played the last time can only give us confidence to go on and do the same this time and hopefully we can beat them again."