Mark Warburton's side - then in the Scottish Championship - eliminated their Old Firm rivals from the competition in an epic semi-final at Hampden in April, winning on penalties.
Rangers, facing Celtic for the second time in four years, twice led the Scottish Premiership winners in a match which showed that there may not be a gulf in class between both Glasgow giants.
Crooks, who signed for Rangers in January, was in attendance to watch his soon-to-be team-mates get one over the old enemy, and from where the 22-year-old was standing - in with the Celtic supporters - it looked as if Warburton's troops gave the Bhoys a lesson.
"Rangers winning was a fair reflection on how the match went. They played them off the park," he said via The Daily Record.
"No disrespect to Celtic but Rangers showed them how to play. I was impressed with how the lads wanted to play football. You could see they enjoyed it and how much it meant to them."
The first Old Firm derby in the league will come on September 10 at Parkhead.
The defender is one of eight new faces at Rangers this summer, joining Jordan Rossiter, Joey Barton, Clint Hill, Niko Kranjcar, Matt Gilks, Lee Hodson, and his friend and former Accrington team-mate Josh Windass.
Crooks is injured but Windass played and score in this morning's 2-1 win over South Carolina side Charleston Battery, with Harry Forrester also finding the net.