Mikael Lustig is still ringing the last few drops out of the party.

Taking Celtic to the Invincibles tag was followed by beating France with Sweden. If Lustig’s summer was to be typified by anything it might have been the photograph which appeared on social media with him and Zach Braff (he of Hollywood Scrubs fame); the defender, though, has insisted that Celtic’s place at the pinnacle of Scottish football is way more than just a quick snapshot.

Lustig will be back at Lennoxtown later this week as the wheels get back into motion. There has been little respite from the physical or mental demands for football but Lustig was unperturbed.

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“To be honest, most summers are like that for me,” he said. “If you are coming off the back of a domestic calendar and going to a World Cup or a European Championships or there are international games, then you tend not to get much longer than maybe 10 or 12 days off for a holiday.

“But I don’t mind that. In some ways it makes it easier because you are not coming back chasing your fitness, you are just coming back to get going again.

“In any way, I think when you are winning and we have just had a season like the one we did then I think everyone goes back feeling good about themselves.

“There is never too much chance to stop and think about what you have done when you are playing. It was a special season but the real chance to appreciate it is probably only going to come when you stop playing and get a chance to truly reflect.

“When you are playing there is always another season, another challenge to think about.”

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The immediate challenge that awaits Celtic lies in guaranteeing the group stages of the Champions League for a second successive campaign.

The three qualifying rounds are a fraught journey and Lustig has experienced both the thrill of qualifying and all that entails as well as the crushing disappointment of failing to make it into Europe’s elite competition.

In both cases, there is a tension and anxiety to the games given the precarious drop if the outcome is not a successful one.

The return leg against Hapoel Be’er Sheeva last season was the most fraught game of Celtic’s entire campaign – Celtic assistant Chris Davies admitted that he spent the game with an agonising headache such was the tension of qualifying – while Brendan Rodgers too admitted that it was the longest game of his managerial career.

And for Lustig it is easier to be out playing than it is to be watching.

“There is tension as players but it is different because when you are on the park you feel that you can control it,” he said. “They are strange games to play in, in some respects.

“There is a different kind of pressure because, like Cup games, all that matters is actually getting through. You can win as ugly as you like – you just want to keep getting through.

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“But it is exciting too and it is a great opportunity. It is frustrating sometimes that you have to go through all the qualifiers but it is important that we are ready for them and I think this year we are in a good place as we get ready for them.

“We have a manager who has been brilliant for the club and brilliant for the players and it isn’t like last year when he had just come in the door. He knows what he has and what everyone can do and that stability hopefully helps us as we look to qualify again.”

Celtic have added Jonny Hayes to the squad while there will be further changes expected over the next couple of months.

Ryan Christie will spend this season in Aberdeen while Scott Allan will be in Dundee. Further fringe players are expected to move on while Rodgers is keen to add at least another two signings to bolster his squad as they look to defend their Treble while also making inroads in Europe.

In any case, Lustig is certain that Celtic’s mentality will not waver whatever tweaks are made to the squad.

“The manager doesn’t let us slip for a minute,” said the Swede. “It is a mentality. Every day we are training at 100%, we are playing every game at 100%. Every game is a big game, every game is one that we expect to win but we expect to win by playing football a certain way.

“Whoever comes into the team will get that right away. The manager has created a certain philosophy and I think everyone can see the results that it got. It is about us doing the same all over again.”