Vidar Riseth has told Celtic 'don't get mad, get even' as they face the nightmare of a Rangers title party at Parkhead.
The former Hoops midfielder knows to his cost what happens when players lose their heads in the heat of Old Firm battle.
The Norwegian was one of three men sent off at Celtic Park as Rangers celebrated a championship win with a controversy-filled derby triumph at the home of their bitter rivals back in 1999.
The red mist descended on Josef Venglos' team, with Stephane Mahe also dismissed by Hugh Dallas before Rangers – who saw Rod Wallace sent for an early bath – cruised to a title-clinching 3-0 win.
While the Ibrox troops celebrated by mocking Celtic's huddle in front of their jubilant supporters, Riseth admits he was racked with shame after the final whistle.
Now Neil Lennon's current crop face a similar fate next month after seeing Rangers move to within seven points of the crown.
If both the Glasgow giants win their next two games, their March 21 showdown in the east end of Glasgow could seal the league for Steven Gerrard's team.
Even without fans, Riseth knows emotions might easily boil over but he has urged Celtic not to repeat the mistakes his side made two decades ago as they look to save some face following a disastrous season.
Looking back on that infamous clash, Riseth, 48, told the PA news agency: "Seeing Rangers winning the league in our stadium is the worst thing that could happen, not only for the players but for the club and the fans as well. That was not a good experience.
"I remember this game. It was terrible.
"We hadn't played well that season of course but we had a good week's training before the game and we actually started the game quite well.
"But once Rangers got in front we just fell apart.
"I remember thinking, 'Oh no, not again' because we had played so many bad games that year.
"We got angry and when that happens, you are behind in everything you do.
"It was a really bad feeling.
"I got a red card in this game – but I wasn't the only one. There were a lot of cards flying about – so many reds and yellows.
"We didn't cope with the situation well and Rangers were able to win the game comfortably.
"I was sent off with around 10 minutes left. I was already in the shower when the other boys came in.
"I just remember the place being so quiet. I don't remember the dressing room at Celtic ever being that quiet.
"To lose the league at home to Rangers is the worst thing. We all felt shame, we felt angry, we were thinking about the fans. We know the rivalry, the fans hate each other so you don't want to give the other side reason to gloat.
"My message to the current team if they end up in the same situation next month is to only think about the next minute of the game. Don't go out thinking I'm going to show the fans something or end up being crazy and kicking someone.
"Of course it's important when you go into a game like this to fight really hard.
"If they can give their all from the first minute then they have a good chance. But if they don't give 100 per cent all the way to the final whistle, then they are going to lose."
Rangers have the title firmly in sight after Celtic's defeat to Ross County on Sunday handed them an 18-point lead.
But Riseth admits he has been left stunned by the fall from grace suffered by the Hoops' nine-in-a-row heroes.
He said: "I saw Sunday's game. Celtic haven't been good this season but why they have been so poor is difficult to say.
"I think they could do with a few new players and some of the players need to go too. I don't want to mention names but I don't think this squad is strong enough to compete with Rangers.
"It's been a strange fall from Celtic but the hardest thing in football when you wins titles is to get yourself up again the next year.
"All the teams behind you want to beat you and if you sleep a little bit they take the chance, like Rangers are doing right now.
"I think Celtic have been sleeping a little bit too much at the moment, that's why Rangers are number one and can win the league at Parkhead next month."
