Not that it will be needed. The Scottish Cup game at Tannadice was a massive game for both clubs for a host of different reasons.
But the appointment of McNamara and Donnelly, two former Celtic players, definitely adds an edge to what will be a fascinating clash.
I have to say, the way Rangers have been playing in recent weeks, I fear the worst for them.
They have been toiling defensively against Third Division players. They have looked vulnerable against Elgin City, Berwick Rangers and Montrose.
So how will they get on against top-quality opponents – the likes of Jon Daly, Gary Mackay-Steven and Johnny Russell – this weekend?
The bookies have installed Rangers as underdogs to win the fifth-round match – they are 3-1 to progress – and rightly so in my opinion.
It will be a tall order for Ally McCoist's young side, many of whom have not been involved in the top flight, to get a result away from home.
Yes, they will be desperate to do well against SPL opposition. And, yes, they beat Motherwell when they met in the League Cup earlier this season. But their form is not encouraging.
I hope the poor results have been down to complacency. With such a comfortable lead in the Third Division, it is understandable that they would switch off.
I think Celtic, who are 15 points clear in the SPL, have experienced exactly the same sort of thing this term. They know if they lose a game here or there it will not matter.
But Rangers can look at St Mirren, who stunned Scottish football on Sunday when they knocked Celtic out of the League Cup at Hampden, for inspiration.
Danny Lennon's team had lost 4-1 at home to Ross County the week before. But they bounced back from that disappointment, and then some, at the National Stadium.
The Rangers players must channel their anger at their embarrassing home draw with Montrose last weekend.
One thing is for sure, Ally will need all of his players performing well for his team to prevail. If only two or three are on top of their games they will lose.
Rangers will probably have to field five or six youngsters – Fraser Aird, Robbie Crawford, Chris Hegarty, Kyle Hutton, Andy Little, Barrie McKay and Ross Perry could all feature.
How they respond to their club only having a few hundred supporters in a crowd of around 10,000 will be interesting.
They are used to playing in front of full houses at home, and with a large travelling support away from home, so it will be a shock to the system for them.
The senior Rangers players – Neil Alexander, Ian Black, Lee McCulloch if, as looks likely, he returns and Lee Wallace – will all have a big part to play in what will be a hugely demanding cup tie away from home against tough opposition.