Kris Boyd has warned Rangers they simply cannot afford to start next week's derby in the same lifeless fashion as last time.
Giovanni van Bronckhorst's team were blown away by Celtic in a brutal evening for Premiership champions back in February.
A double from Reo Hatate and a third from Liel Abada swung the title race momentum towards Glasgow's east end and it's the Parkhead side who enter the April 3 clash as league leaders.
That result was built on a lightning fast opening half from Ange Postecoglou's players and Boyd, who was back at Ibrox on Saturday for a legends match, insists Rangers must ensure it does not happen again.
He told Sky Sports: “You are going to have to start the game a lot better, sharper, brighter than you did [at Celtic Park].”
“The game was over at half-time, effectively, after the start Celtic got.
"Going into the game, Celtic, there would have been nerves there because you haven’t beaten Rangers for a long time, but when you get that goal so early, you’re pushing and the fans are right behind you.
“To lead 3-0 at half-time I don’t think even Celtic fans would’ve expected that, but that’s exactly the way the game panned out.
“Rangers came out in the second half and tried to get back into it.
"There’s some encouragement to be taken from the second half and I’m sure that will be message Giovanni van Bronckhorst tries to get across to his players. It’s difficult with international fixtures this week as well.
“The damage was done in the first half for Rangers and it shows you if you don’t start a game properly you’ll get punished.”
Rangers were without talisman Alfredo Morelos and he will be assessed by Rangers' medical team after returning to Scotland early from Colombia duty on Saturday.
The striker has been nursing a muscle issue and has been granted permission to travel back to Glasgow after sitting out Thursday's win over Bolivia.
A statement from the Colombian Football Federation said: "The technical and medical staff of the Colombia Men's Senior National Team reports that, after performing medical tests on player Alfredo Morelos, a muscle injury in the left thigh was confirmed, which prevented him from participating in the previous match against Bolivia and likewise does not allow him to participate in the next match of the qualifiers for the FIFA World Cup Qatar 2022.
