HOW do you improve upon perfection?

That is the question which Celtic players will be faced with at the start of next season if they can round off their exemplary campaign by avoiding defeat in their last three Ladbrokes Premiership matches and then lifting the William Hill Scottish Cup final.

It will be very hard for them to top going unbeaten in 47 matches domestically and landing what would be only the fourth treble in their 129 year history.

But not, according to Callum McGregor at least, impossible.

Read more: Celtic as good for Scott Sinclair as he has been for Celtic, says Brendan RodgersThe Herald: Celtic's Callum McGregor models the Parkhead club's new kit for the 2017/18 season.

McGregor has enjoyed an exceptional spell personally for Brendan Rodgers’s all-conquering side in recent months. The goals which he scored in back-to-back games against Rangers in the cup semi-final at Hampden and league match at Ibrox in April were undoubtedly the highlights.

However, he is still adamant that both he and the Parkhead club can fare even better in the 2017/18 term - by making a far greater impression in European competition.

Celtic qualified for the group stages of the Champions League for the first time in three years back in August and went on to draw with English rivals Manchester City home and away and German opponents Borussia Moenchengladbach away.

McGregor, though, revealed that progressing to the knockout rounds of a continental competition is a major ambition going forward and one which he is confident they can realise.

Asked what the Scottish champions’ objectives would be for next season, he said: “More of the same, really. We’ve got to keep the hunger and continue to progress. The beauty of all this is the manager wants us to get even better even though we’re playing well just now. We must keep the hunger and work ethic.

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“We’ve got to think there’s more to come from this side. We can’t rest on what we’ve done this season or the season before. We will come back in the summer with a fresh hunger to go again and be even better.

“When we sit down and assess where we’re going next season to go and really progress in a European competition could be a target for us. We seem to be getting better and better and I don’t think it is beyond us that we could go and have a run.”

McGregor, who had never been involved in the Champions League group stages before this season, is confident the Celtic players will have benefited enormously from their meetings with Barcelona, City and Moenchengladbach and will be better prepared for their opening qualifying match in early July.

“The team is getting better and better,” he said. “We’ll have a better idea going into these games than we did last season when the new manager had just come in. We always know these games are difficult to get through and you need a bit of luck as well. We saw that last year, but hopefully we’ll be in a better place than we were 12 months ago.”

That is certainly true to McGregor himself. The midfielder has gone from being a useful fringe player who brought youthful energy and honest endeavour to the Celtic side whenever he was given a run-out to a regular starter with the intelligence to engineer an opening and the composure to convert a chance on even the biggest of occasions.

The 23-year-old, who is hoping to be involved in the league meeting with second-placed Ab-erdeen at Pittodrie tomorrow evening, admitted that his life had changed, especially after his goals against Rangers.

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“The last couple of weeks have been amazing,” he said. “Scoring in back-to-back games against Rangers was something else. You see the fans everywhere and when I’ve gone for a coffee everybody has been saying well done.

“It gives you a real boost and it shows you how far we’ve come in 12 months having lost the semi-final last year. It’s a total contrast for me personally.”

McGregor stressed that Rodgers must take enormous credit for how he has flourished. “The manager has given me massive confidence and it’s been a big factor for me,” he said. “He’s singled my performances out once or twice now too so that’s great for my self-belief.”

The Scot has even been tipped to win a call-up to the full national team ahead of the Russia 2018 qualifier with England at Hampden on June 10 as a result of his lively displays.

“It’s obviously an ambition,” he said. “All I can do is put the performances in on the pitch for Celtic and we’ll see what happens. I’m enjoying my football right now, but it’s a massive ambition to play for my country.”

Having taken time to establish himself in the Celtic side, however, McGregor isn’t getting carried away with his sudden rise to prominence. He is grateful to be part of such a successful side and is determined to remain involved in what he anticipates will be a bright future.

“It’s good that people are noticing my performances,” he said. “But just being in the team has been something special. That’s because we’re all part of something special this season. I don’t take any of that for granted.”