Neil Lennon knows just how much home advantage can play its part - especially at some of Europe's most intimidating grounds.
He played over 200 times for Celtic, including being involved many iconic night's under the floodlights.
The Scottish Premiership leaders travel to face Borussia Dortmund tonight hoping to produce a momentous European result.
Celtic got off to the best possible start by thrashing Slovan Bratislava on matchday one of the UEFA Champions League, but the tests get tougher with the Bundesliga giants the latest opponents standing in their way.
"It was difficult," Lennon stated as he reflected on previously playing on the Signal Iduna Park turf.
"But we were playing against Germany with (Lothar) Matthaus, (Jurgen) Klingsman, and people like that. It's like Celtic Park, Celtic Park can maybe not intimidate the opposition but it can bring the best out of the home players, which is probably what Dortmund want to do here.
"Their home form so far has been decent. I'm under no illusions this is a step up for Celtic in terms of the quality of opposition, but there's a quiet confidence about Celtic at the minute, and the manager is producing the goods now."
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Fellow TNT Sports pundit, Owen Hargreaves, also thinks it will be a tighter game than many expect, particularly because last year's competition runners-up lost several key players during the summer.
"There's been a lot of change at Dortmund," the ex-Bayern Munich midfielder explained.
"I think the modern thing now is to go for a young manager. Nuri Sahin was a really good ball player, played for Borussia Dortmund and went on to Real Madrid. But he's a technical player.
"I think Borussia Dortmund is a bit like Celtic in a way as a club, it's a huge powerful football club with these most amazing fans and great traditions. So I just think as a young manager it's a huge job to go and take on a club like that.
"He's already had one big loss against Stuttgart (5-1), and the thing is at a big club you can't really have that many big losses as a young manager, so there's been a lot of chopping and changing. This is a huge test for Nuri Sahin tonight.
"I think this team is weaker than last season and they have a less experienced manager so I think Brendan Rodgers will be licking his lips.
"Obviously it's difficult to go and play at Dortmund, it's one of the best stadium's in world football. But I think for Celtic today if they get it right, they can win this game."