Celtic must summon the spirit of 2006 to repeat a famous victory over Manchester United on Wednesday and maintain an interest in the Champions League.
Two years ago Shunsuke Nakamura's late free kick secured a 1-0 Parkhead win over United that helped Celtic into the knockout phase for the first time but this year the Scots, with one point from three games, are hanging on by their fingertips.
They were disdainfully swept aside 3-0 at Old Trafford last month as two goals for on-song Dimitar Berbatov and one for Wayne Rooney capped an impressive display by the champions.
Another win for United would send them into the last 16 with two games to spare if AaB Alborg fail to beat Villarreal in Denmark and a draw would be enough if the Spaniards win.
Celtic have lost only one of their last 11 home Champions League games but they are yet to score in three matches this season and United are yet to concede.
United's defence was given a wake-up at the weekend, however, when Hull City had the temerity to score three times at Old Trafford, leaving Alex Ferguson's team hanging on for a 4-3 victory having led 4-1.
"We got a warning on Saturday, we have to make sure we finish teams off, goalkeeper Edwin van der Sar told MUTV.
"We must not stop halfway through the second half and start thinking about the next game."
Celtic warmed up with a 2-0 win at Hearts that took them back to the top of the Scottish Premier League and manager Gordon Strachan dismissed suggestions that there was a massive gap between the two British leagues.
"We didn't play as well as would have liked (at Old Trafford) but Man United are probably the best team in the world," Strachan said.
"Roma went there and got beaten 7-0 but no-one said there was a big gulf between Italian football and English football, West Ham went to Old Trafford last week and it was 2-0, it could have been six. West Brown went there and lost 4-0.
"Everyone who goes there, who has spent more money than us, has got a right tonking there. We got beat 3-0 but two of the goals were offside so it's not as bad as people have been making out."