IF you want to start a fight in an empty house with a Celtic supporter then bring up the subject of James Forrest.

Indeed, there doesn’t have to be a house. Or even a supporter. You just know that somewhere a heated debate is taking place about the winger who over the past seven years many have sworn by, while quite a few others have simply sworn at.

He is a bemusing footballer.

On Tuesday night against Bayern Munich, Forrest produced arguably his finest performance in a Celtic jersey. From his first touch to the beautifully judged pass for Callum McGregor which led to a goal – and there were quite a few successful dribbles in-between – he was the best player on a pitch packed with talent.

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Most wingers are inconsistent, it goes with the position they play, but the Celtic man can take blowing hot and cold to ridiculous levels.

Forrest tends to save his best for the biggest stage. The other night a prime example. But then a few days later he can struggle against a Hamilton full-back. However, when he’s good, this guy truly is something else.

“James was absolutely terrific against Bayern,” enthused Stuart Armstrong. “His link-up play, his balls into the box,the through ball to Callum for the goal, all of it was outstanding.

“It was his overall play. He was a threat all night. He was a fantastic asset for us during the game.

“It’s been tough for James, what with there being a lot of competition for places. He’s been out of the side at times but he showed in front of a full Celtic Park and against top quality opposition that he’s one of our best.”

Forrest actually began the season brightly but lost his place to Patrick Roberts who most likely would have started the Champions League match had he not succumb to a hamstring injury.

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Many supporters, let’s be honest. would have walked to the game worrying that the on-loan Manchester City man was to be replaced by a player who has been booed, albeit mildly, at Celtic Park.

My goodness, but he prove those doubters wrong.

Forrest is four games away from his 250th in Celtic’s colours, has 11 major honours to his name and his goals, when they come, are vital.

Armstrong was asked whether his team-mate was an unsung hero and the midfielder said: “Sometimes that can be true. He’s been at the club for a long time. He’s a quality player and we get to see that every day in training.

“He showed against Bayern what a top quality player he is when he takes it to the next level.

“Sometimes injuries give opportunities to other players and Jamesy has certainly taken that in his stride. I’m really pleased for him.”

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The Celtic players were far from jubilant in the wake of what was a second successive home defeat in the Champions League which meant they were out of the competition with still two games to play.

However, while by all accounts the dressing room was a quiet place to be in the aftermath of the 2-1 loss, a sense of perceptive seemed to have been gained by the time the players fulfilled their media duties.

Celtic should still finish third and when you take into account the clubs that don’t look like finishing at least second, Benfica, Atletico Madrid and Sporting Lisbon to name but three, it shows how difficult this competition is.

Brendan Rodgers’s side are not yet where the manager want them to be; however, with academy graduates Forrest, McGregor and Kieran Tierney, superb once again, all playing on Tuesday, the future is bright.

“All the boys are really pleased Kieran has signed on for a length of time and the fans are obviously delighted,” said Armstrong. “Against Bayern he just played his usual game and was terrific.

“It’s rare you find a player at a club who has supported them since he was a boy. He grew up watching Celtic play and now he’s one of the mainstays of the team. It really is a dream come true for him and we are lucky to have him.

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“It’s bizarre seeing the pictures of a young KT in the tracksuit as a ball boy here, then in the youth team. It’s inspiring to see a boy like that make it into the Champions League.

“There’s no denying he absolutely loves Celtic and playing for Celtic. But we all do. As soon as you come to Celtic, you are hit with a realisation that it’s an enormous club and you grow to love it.”

For Armstrong and his team-mates, it now all about making sure they finish above Anderlecht, which they really should do, and then comes the Europa League and a chance of making their way through a few rounds.

“There are certainly a lot of positives for us, going forward and controlling the game against one of the very best teams in Europe. Our aspiration is to be in the Europa League after Christmas.”

As consolation prizes go, there are a lot worse.