Of all the Champions League matches taking place this week, none will generate more passion than the meeting of Celtic and Manchester United on Tuesday.
Two clubs with fanatical support, sizzling form and passionate Scottish coaches will meet at Parkhead with United, as Group F leaders, knowing victory will guarantee themselves top spot and a place in the last 16.
Celtic, who have racked up 11 straight wins in the Scottish Premier League including the 3-0 victory over Inverness Caley Thistle at the weekend, are just three points behind United and can sense a place in the knockout round for the first time.
Despite an apparent thawing in relations between Celtic manager Gordon Strachan and United boss Alex Ferguson, both will be desperate for victory on Tuesday.
Strachan, who played under Ferguson at Aberdeen and then at Old Trafford, knows that ultimately he will be judged on progress in Europe, however dominant his side are at home.
Ferguson, a native of Glasgow and one of the most successful manager in the world game, knows exactly what to expect.
"We will need to show courage and mental strength to handle the atmosphere at Parkhead (Celtic Park)," said Ferguson, who believes his current side can go al the way.
"I expect the game to be exciting, open and full of attacking football -- just the way it was when we beat them 3-2 in September."
Both managers have been critical of eachother in their respective autobiographies, Strachan blasting Ferguson's management style and Ferguson saying Strachan "could not be trusted".
The mind games have already started with Ferguson opting to take the pre-match press conference away from Celtic Park.
United will stage the news conference at their hotel on the edge of Loch Lomond on Monday and have also shunned the customary pre-match training session at their opponents' ground.
They will train at their Carrington complex on Monday morning before flying to Glasgow.
Ferguson has been quick to smooth over his relationship with Strachan and Sunday's newspapers suggested "peace had broken out" between the two men.
"I want to win at Celtic Park because it's important to finish first in the section," Ferguson told the Sunday Mail.
"But I'd also like to see Celtic finish second. It would be great for them and Scottish football. I'm keen to finish the job in Glasgow though.
"We wanted to do it against FC Copenhagen earlier this month, but lost 1-0."
Wayne Rooney was in scintillating form for United against Sheffield United on Saturday, scoring both goals in United's seventh successive league win, and will relish the big-match atmosphere at Celtic.
While Ferguson has no injury concerns, Celtic striker Kenny Miller has been out with an ankle knock and defender Gary Caldwell limped off with a knee injury after an hour of the Inverness game on Saturday.
However, Strachan is happy to have Jan Vennegoor of Hesselink and the gritty Thomas Gravesen available.
"It will help us with Jan Vennegoor of Hesselink and Thomas Gravesen coming back because we missed that bit of experience at Benfica," Strachan said, referring to the 3-0 defeat to the Portuguese side in their last Champions League outing.
Probable teams:
Celtic: 1-Artur Boruc; 2-Paul Telfer, 3-Lee Naylor, 6-Bobo Balde, 44-Stephen McManus; 16-Thomas Gravesen, 25-Shunsuke Nakamura, 18-Neil Lennon (capt), 46-Aiden McGeady; 9-Kenny Miller, 10-Jan Vennegoor of Hesselink
Manchester United: 1-Edwin van der Sar; 2-Gary Neville, 5-Rio Ferdinand, 15-Nemanja Vidic, 3-Patrice Evra; 7-Cristiano Ronaldo, 16-Michael Carrick, 18-Paul Scholes, 11-Ryan Giggs; 9-Louis Saha, 8-Wayne Rooney.
Referee: Manuel Mejuto Gonzales (Spain)