Talksport host Alan Brazil says Sunday's Old Firm result showed that Rangers have a brighter manager than Celtic.
Mark Warburton's Championship side were more than a match for their Premiership opponents in the semi-final of the Scottish Cup, eventually beating them 5-4 on penalties after twice being pegged back at Hampden Park.
The defeat made Ronny Deila's position as Celtic boss even more perilous, and Brazil has urged the Bhoys board to wake up ahead of next season - when the Glasgow rivals will compete in the top division.
"It’s quite simple," Brazil said while presenting the Sports Breakfast show on Monday. "Warburton’s tactics early on - the way they flooded the midfield... Quite clearly he’s much brighter than the Celtic manager - totally brighter."
Brazil, who had a successful career as a striker in English football, was born in the Govan area of Glasgow and played for the Celtic Boys Club as a youngster.
He added: "If the Celtic directors don’t understand that now then it’s going to be one helluva season next year."
Deila arrived from Tippeligaen side Stromsgodset two summers ago and is on a 12-month rolling contract at Celtic, meaning his departure should be fairly straightforward.
Former Bhoys defender David Moyes and Deila's predecessor Neil Lennon are the two clear favourites to replace the Norwegian at Parkhead, according to Oddschecker.