That's one of the connotations of European nights in Parkhead, with the pitch basking in the bright glow of the floodlights and the blades of grass fluttering as the fervour of the fans' roars reaches them.

The voltage was cranked up, the "disco lights" had made their way onto thousands of Instagram stories and Leverkusen, with only Bayern Munich ahead of them in the German Bundesliga, were ready to get involved in a game in which they were heavy, heavy favourites to triumph in. Comfortably. 

I'm sure they didn't expect Celtic's bulb to blow with the shrill blast of the referee's whistle at 8pm, but they must have felt a little electric shock with the verve and pace with which Celtic started the game.

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A disallowed goal in the first minute could have threatened to throw Celtic off their game but they rallied and forced Leverkusen back. Kyogo Furuhashi's two chances should have seen Celtic take the lead; Jonathan Tah wonderfully thwarted him eight yards from goal after he rounded goalkeeper Lukas Hradecky and soon after the same defender decided he couldn't be bothered chasing the Japanese international, relinquished the responsibility on his shoulders by trying to spring the offside trap, which failed, before he breathed a sigh of relief as the energetic forward's shot was well saved by Hradecky.

The Finn then stopped Carl Starfelt from scoring his first Celtic goal and at this point, there's a large degree of optimism and confidence swirling around Celtic Park. Three good chances to score had come and gone, thanks to great defending or goalkeeping on each occasion, but the voltage was being turned up by the minute. Celtic were intent on having a go and following through on their manager's mantra in front of an aroused home support. 

The problem from there is when the circuit breaker trips and Leverkusen capitalise on an almost inevitable, careless, naive Celtic mistake, it feels irreversible. 

The energy put into the performance and support in the first 20 minutes leaves the players and support with zapped, dazed bodies. If this is the way they are going to approach games, even against superior opposition, they simply have to take advantage in the game's opening stages as they did domestically against Dundee, St Mirren and Hearts.

Even in Europe, it's no guarantee it'll be enough - as was seen a few weeks ago in Seville.

As soon as the balance of play tips in favour of the opposition, Celtic look like they don't believe in what they're trying to do. The passes aren't played with as much zip and the runs aren't as dynamic. The belief levels, from the outside looking in, come across as fairly low.

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After Leverkusen's second, I'm not sure many, if any, believed a comeback was possible as the breaker was flipped to "on" at the interval. The undulating crackles and sparks from the stands become a low, gentle hum at best.

The second half followed a similar pattern to the first; Celtic flew out the traps, missed a few chances including an Abada sitter, and looked threatening for 15 minutes. A few in the stands may have turned to their neighbour and uttered, "It's coming..."

Leverkusen's third, from a harsh penalty awarded for Carter-Vicker's handball (I know, I know, it's the game's lawmakers at fault, not the ref), proved to be the second half's trip and there was truly no way back this time. No tactical engineer or motivator could sort that out. No 15 minutes to reset, replenish and refocus.

Leverkusen saw the game out with absolute ease, coasting towards their top of the table clash with the Bavarians on Sunday. For Celtic, it's yet another must-win league game, this time against Aberdeen.

Both are badly out of form but with McGregor and Kyogo back in the team, should have enough. The question is, what on Earth is now expected of Celtic if they fall behind?