Engels put in a complete midfield display which included a goal, an assist, four shots, while only centre-back Liam Scales made more tackles and won more duels.

In the 89th minute, he was pressing high and winning the ball back before celebrating vehemently with the crowd.

"He's a class act," former Scotland forward James McFadden said on Sportsound. "You can see the confidence.

"Sometimes you see players who move for big money and you think: 'How are they going to cope with that pressure?' Especially at a young age.

"He's recently turned 21 but he is class. He's so comfortable on the ball and his understanding of playing in that midfield position well.

"He knows when to go high, when to tuck around. His reading of the game, he's tracking back and covering his team-mates."

Engels is emblematic of Celtic's summer strategy.

Fans have grown frustrated in recent years at a perceived lack of ambition from the club when it comes to improving in Europe, while others would say it is hard for a club of Celtic's means to add the quality and depth needed to compete.

But there was no question repairing recent damage in Europe was a key part of Rodgers returning to Celtic.

And, after an imperfect first season, the sale of Matt O'Riley to Brighton in late August sparked an late flurry of signings, with Engels topping the bill.

"It was great identification by our recruitment team," Rodgers explained.

"We knew after last year what we wanted in the team which is someone who has all the ideas we want in terms of tactical and technical ability. But at this level you need to have a physicality and running power.

"We knew he was playing in a top league and we felt we could take him here and improve his game.

"I'm pleased for him he gets his goal but the overall performance from him and the team was very pleasing."

Celtic, and Engels, will face much sterner tests in the Champions League.

Next up it's a trip to face last season's finalists Borussia Dortmund, and then another away game at Europa League champions Atalanta.

However, favourable home games against Young Boys and Club Bruges, plus an away trip to a Dinamo Zagreb side who conceded nine to Bayern Munich, mean a place in the play-off round, at least, is a distinct possibility for Celtic.

And while Engels was a standout in midfield, it was a terrific team performance full of intensity which got the job done in such style against Slovan Bratislava.

Nonetheless, the Belgian will surely play a key part and his message is he is just getting started.

"A lot," Engels told BBC Scotland when asked how much he can improve. "I'm only here one-and-a-half weeks or so.

"I need to build relationships with the guys and work on every detail in training. And also seeing images from my game will help me improve.

"I hope it will only get better - I think so."