THE divide between Celtic and Rangers is arguably greater now than it has been at any time in the past.

The former have won the Scottish title three years running and have qualified for the knockout stages of the Europa League this season.

The Parkhead club, too, have a financial model and a bank balance that is the envy of many major clubs across Europe.

The latter, meanwhile, are struggling to win promotion out of the second tier of Scottish football and their manager has tendered his resignation after some poor results.

Off the pitch, meanwhile, there is major unrest as fans continue to vent their fury at the running of an institution that needs to find fresh funding to stay afloat.

In addition, the two clubs' respective build-ups for the League Cup semi-final on Sunday could hardly have been more different.

Celtic go into the match at Hampden on the back of a four-game winning run that has sent them three points clear at the top of the SPFL Premiership.

Rangers, on the other hand, have had a game against Hearts abandoned and a match with Cowdenbeath postponed in the last fortnight due to the winter weather.

No wonder, then, that bookmakers have made Ronny Deila's side strong favourites to prevail against Kenny McDowall's charges at the National Stadium.

But former Hoops striker Mark McGhee warned his old club that anything can, and very probably will, happen, in the Glasgow derby match.

The Scotland assistant manager is a veteran of several epic encounters between the rivals and knows only too well that they often don't go according to script. And he feels that, for all their troubles, Rangers are more than capable of raising themselves on the day and claiming victory over Celtic.

He said: "You would expect Celtic to be favourites because Rangers have suffered terrible losses in terms of the quality of the squad they have.

"They have been playing in the lower divisions of Scottish football. They have had financial constraints that have limited them greatly on the park.

"But the one thing they will get is that extra energy from the fixture. Whatever divide there is in terms of experience or ability between the teams will be partly bridged. I think the energy and enthusiasm of good old Old Firm competition will mean that Rangers are able to compete with Celtic on the day."

McGhee, who spent five years at his boyhood heroes Celtic in the 1980s, knows from personal experience that form can go out of the window in the Old Firm fixture.

He watched as Graeme Souness's side smashed five goals past Billy McNeill's disbelieving team at Ibrox in the opening Glasgow derby of the 1988/89 season.

But the former Aberdeen hitman was on target in a 3-1 triumph the next time the age-old adversaries clashed, at Celtic Park.

He feels the enormity of the occasion and the effect of the atmosphere generated by both sets of supporters make it a difficult match to predict an outcome in.

He said: "I had been a Celtic supporter growing up and I had seen a lot of Old Firm games so that helped to prepare me for making my debut in it.

"And the Aberdeen v Celtic and the Aberdeen v Rangers games became big matches in the 1980s. Not quite with the edge of the Old Firm games, but close enough that you understood it.

"Having said that, the intensity and energy around those games was different. It really was. You really felt plugged in when you were preparing for that game.

"When you went into the dressing room and went out on to the park before kick-off there was an edge to it. That was only there at those games."

McGhee continued: "As a player you could definitely feel the anticipation building in the days prior to the match. We would all be hoping and praying that we would be playing. Nerves were always a little bit frayed in the Old Firm week.

"You don't really play in Old Firm games for points - you play for pride, for honour and for bragging rights. Legends are formed in these games.

"Players can ingratiate themselves to supporters forever by scoring a goal or doing something special. Whoever scores the winner this weekend will never be forgotten."

McGhee enjoyed some memorable triumphs over Rangers with Celtic - including in his last-ever appearance for his childhood idols, in the Scottish Cup final in 1989.

That 1-0 victory at Hampden, achieved courtesy of a controversial Joe Miller goal just before half-time, prevented Rangers from winning the Treble.

The man who helped a Celtic side managed by European Cup-winning captain McNeill land a dream league and cup double in their centenary year in 1988 is looking forward to the game on Sunday.

He remarked: "I think Scottish football is less without it. These iconic games in any country are a big part of the season.

"You look forward to the Old Firm games. We all do. Everyone does. It will good to have one. Just don't ask me who will win it. Celtic will be strong favourites to come out on top.

"But you can't write off Rangers."