JOHN COLLINS, the Celtic assistant manager, has warned his players the challenge of beating Qarabag FK of Azerbaijan is a significant step-up for them and that only their best will do against such dangerous opposition.

The first-team squad have studied extensive footage of their opponents over the past few days and the general consensus is that Ronny Deila's men need to produce the strongest of performances over the two legs if they are to get through to the Champions League play-off round, the final hurdle before entry to the group stages.

Celtic will likely have to do without Charlie Mulgrew, a knee ligament problem has kept him out of training since the weekend, for this home match tomorrow night which the Scottish champions will look to win and avoid conceding ahead of the return in Baku.

Azerbaijan is not a country anyone would immediately associate with football, good or bad, but Collins made it clear this qualifier was anything but a foregone conclusion.

“They are a good football team,” he said. “They have good movement, they like to knock the ball about and have pace in the wide areas. They’ve got a couple of Brazilians in the side who are very handy indeed.

“We know Qarabag did very well in the Europa League last year. They drew with Inter Milan and beat Dnipro. They had a tough group but played well in all the matches.

“I wouldn’t want to compare them to any other team. What I can say is they are very well organised tactically. Physically they are in good shape and they have skilful, technical players. They are champions of their league so are a good all-round team. But so are we.

“They are no mugs. We will have to play well to get through. It should be a good game. It certainly won’t be easy.”

Collins believes that the supporters will have realised that despite Qarabag’s lack of European pedigree that this is a challenge not to be taken lightly.

“Celtic fans are not daft,” he said. “Not many people will have heard of them but if you do a bit of research you see how well they did last year. There’s no household names in their team, that’s for sure, but they have a few Brazilians and internationals who are very good football players.

“If you can keep a clean sheet and score a few goals that would be the dream scenario if you could write the script. We are at home and of course, we want to entertain and score goals. Equally important is keeping that clean sheet."

Collins also admitted that should Celtic go out of the Champions League at this stage, there is every chance that Virgil van Dijk would leave during this transfer window.

Everton manager Roberto Martinez did not try to hide his own admiration for the Dutch centre-back at the weekend, although the Celtic No2 once again made the case that a season playing Champions League football would benefit a player he is close to.

“Will it be more difficult to keep him (if Celtic go out)? Probably. Hopefully we won’t have to deal with that scenario,” said Collins.

“If you are a centre half playing in the Champions League you are up against the best forwards in the world. It’s a great challenge and if you do well in the Champions League it puts you on a different level."