RED Bull’s newly-installed Head of Global Soccer Jurgen Klopp may be asking some difficult questions about why Nicolas Kuhn was allowed to depart RB Leipzig in the coming days after this crushing Champions League loss to Celtic at Parkhead.

Kuhn, who spent three years in the youth ranks at the Saxony outfit when he was a teenager, was inspired against his old employers and scored two first half goals to ensure the Scottish champions ran out worthy 3-1 winners in their fourth league phase match.

Brendan Rodgers’ men increased their chances of reaching the knockout rounds of Europe’s premier club competition for only the fourth time in their history with a scintillating display and richly-deserved result.

Reo Hatate also got his name on the scoresheet in the second half to wrap up the three points. However, the margin of victory could and really should have been even greater than two.

It was a far cry from the Glasgow club’s previous encounter with German opposition – the 7-1 mauling they suffered at the hands of last year’s beaten finalists Borussia Dortmund last month.

Here are five talking points from a memorable night in the East End.   

Trust in Trusty

Liam Scales was named Man of the Match after Celtic’s two previous Champions League home matches against Feyenoord and Slovan Bratislava.

But the Republic of Ireland internationalist found himself on the bench as Auston Trusty started alongside Cameron Carter-Vickers at centre-half.

It was - while harsh on Scales, who has been excellent at home and abroad once again this term – not a huge surprise given that summer signing Trusty was preferred in the meetings with Dundee and Aberdeen last week.

Could the all American pairing, who had kept two consecutive clean sheets together, gel and repel the twin Leipzig strikeforce of Benjamin Sesko and Lois Openda?

Trusty required medical attention after landing awkwardly in the eighth minute. But he dusted himself down and was soon back on the park. He and his fellow defenders had little to do until their opponents won a corner in the 23rd minute.

Carter-Vickers failed to clear the Kevin Kampl delivery and Christoph Baumgartner  nodded in at the back post to break the deadlock. 

But Carter-Vickers was immense after his uncharacteristic lapse in concentration and Trusty more than justified his selection too. Scales took over from his vice-captain at 3-1 and did well. But the United States internationalists will be difficult to displace going forward.

Kuhn class

Celtic rued their failure the capitalise on the early pressure they put Leipzig under during the opening exchanges when Baumgartner scored. They dominated possession after kick-off and got into good positions to net on a few occasions. But they failed to take advantage of any of them.

Arne Engels had an attempt block after being supplied by Daizen Maeda, Kyogo Furuhashi was unable to get on the end of a delightful Kuhn chip into the six yard box and nobody was alert enough when the winger then squared the ball across the face of goal.

The German took matters into his own hands after the hosts had fallen behind and levelled with a sublime equaliser. He cut inside after receiving a pass from Engels and curled a shot beyond Peter Gulacsi and in off the inside of the left post despite the close attentions of El Chadaille Bitshiabu.

He was in the right place at the right time in the Leipzig area during the first minute of added on time at the end of the first half following excellent work by Hatate and Greg Taylor. He put the home team in front at the perfect moment and raised the roof inside Parkhead.  

There were mixed reports from Austria about the wide man when he arrived in Scotland from Rapid Vienna back in January. It is hard to understand why. The 24-year-old has performed consistently well, firmly established himself in the first team and become a real fans’ favourite.

Kuhn is said to be attracting the interest of a few Premier League clubs in England. His display against Leipzig will have increased his value by a few million. But Celtic supporters will be praying he stays where he is for the foreseeable future.   

Flat Red Bull

RB Leipzig may have been level on points with mighty Bayern Munich in the Bundesliga until they lost to Borussia Dortmund in the Westfalenstadion on Saturday. But it was not difficult to see whey they had nil points in the Champions League following losses to Atletico Madrid, Juventus and Liverpool.

The 4-2-2 formation which Marco Rose favours did not function well at all. Callum McGregor, Hatate and Engels bossed the middle of the park, starved Sesko and Openda or decent service and helped to create numerous scoring opportunities.

Strength in depth

Rodgers took off Carter-Vickers, Engels, Furuhashi, Taylor and Kuhn and put on Scales, Paulo Bernardo, Adam Idah, Alex Valle and Yang Hyun-jun in the second half with no discernible drop in performance level. Having so many squad members capable of competing on such a stage augurs well for their forthcoming matches.

No pyro, no problem

That Scottish football has a serious pyrotechnic problem has been glaringly obvious this season. Not least in European competition. Supporters of both Celtic and Rangers have set off flares, smoke bombs and rockets and earned their clubs hefty fines from UEFA.

Kick-off in both of the Premier Sports Cup semi-finals at Hampden at the weekend were delayed because of poor visibility in the stadium caused by thick clouds of smoke.

The display before the Champions League match against Borussia in Dortmund last month brought a one match suspended away fan ban from European football’s governing body.

Rodgers appealed to the hardcore element among the Celtic support to leave the fireworks at home for their Bonfire Night cracker and they listened. No pyro? No problem. The absence of incendiary devices did not detract from the atmosphere in the slightest.

It is, of course, far more of an issue at away grounds. Will the young team behave when they take on Dinamo Zagreb in Croatia next month? Watch this space.