New Celtic winger Jonny Hayes has admitted that his side face a "hard" battle to qualify for the group stages of the Champions League.

The Scottish Premiership champions begin their European campaign with a two-legged tie against Linfield of Northern Ireland this Friday in the second qualifying round, with two more rounds then to come ahead of the group stage.

Brendan Rodgers's side reached the group stage last season but went on to exit the competition without registering a single win in what was the only low point of an otherwise blemish-free season for the Hoops.

"It is still a long way away, Champions League football," Hayes, who joined Celtic from Aberdeen last month, told reporters. "Six tough games between now and getting there. We're under no illusion how hard it is going to be to get there. But yeah, of course, it's the best competition in the world.

"I think I've settled in very well [at Celtic]. I know how the manager wants us to play, obviously there is the added bonus of being with the international team over the summer keeps you on your toes, I didn't have time to lose that sharpness.

"I only got three or four days off I think. I'd take it to be honest. Football is different now, it's a modern game where players look after themselves. There are no more days of going to the pub after training, you'd be caught out fairly quickly if you did.

"You love going away with the international team. But in the back of your mind, you're thinking that makes pre-season a little bit easier now. That's the way I looked at it anyway. So, I was up and running again, fitness-wise you're not going to lose much in just a few days off. I'm raring to go since I signed. Playing competitive games is the next step forward."

Rodgers's men travel to Linfield for the first leg, with the return at Celtic Park next Wednesday.