PATRICK Roberts is a Manchester City player again this morning, a 20-year-old man with the football world at his feet.

But such a hold has Celtic exerted on him over the last 18 months that, listening to him at Hampden Park on Saturday, that you might have believed that he was a washed-up has-been whose biggest achievements in the sport are already behind him.

No sooner had the Londoner played the last match of his productive loan spell, than he was conceding that playing his part in the first ever invincible treble in the history of Scottish football was the kind of achievement he may never surpass.

Read more: Callum McGregor: I'm gutted to be overlooked for Scotland v England .. but becoming a treble invincible will make up for itThe Herald: Celtic's Patrick Roberts hold up a shirt in support of Kieran Tierney at the final whistle. Picture: SNS

"I don’t know if I’ll ever play for a team who can go a whole season unbeaten – invincible," said Roberts. "So I think, when I look back on my career, this will be the biggest highlight – my biggest accomplishment in the game. It’s good to get that so young, although I hopefully have a big career ahead of me."

Whatever Roberts does or does not go on to achieve, the truth is that battling it out for titles on stages like this at such a tender age usually tends to be the making of a young footballer. The task facing him when he returns to the Etihad this summer didn't get any easier when Pep Guardiola sanctioned the arrival of Monaco's Bernardo Silva for a fee in the region of £43m, but Celtic has prepared Roberts well for whatever awaits him and would take him again in a heartbeat if they can find a way to get the deal done.

"Experience is crucial these days, especially for young players – and that’s what I’ve got here," said Roberts, his voice choking with emotion. "If you’ve played in big games, managers know they can trust you, which is important. So coming to Celtic and winning four medals is very big for me. I can take that into the rest of my career."

Read more: Callum McGregor: I'm gutted to be overlooked for Scotland v England .. but becoming a treble invincible will make up for it

For all the talk of the once-in-a-lifetime nature of this achievement, Celtic aren't getting any weaker and Roberts for one would back them to do another treble next year - with or without him. "It’s a tough achievement," he said. "To do it next year? It will be tough – but I’m sure this Celtic team have the ability. For me? If it is a goodbye, it will be a tough goodbye. Because it’s a massive club. They took me when I was only 19 and to go on loan at a club like this is massive. I’ve been given an opportunity to play in truly massive games, to win trophies and win titles. It’s more than I could have asked for."

Saturday's outcome fully vindicated Roberts' decision to decline a call-up for the England squad for the Under-20 World Cup. Having seen his second half shot tipped onto the post by Joe Lewis, he briefly thought that the Parkhead side might fall at the final hurdle. "I think the thousand shots Griff had were making me think it wouldn’t be our day!" joked Roberts. "No seriously, when I hit the post, I was thinking that on another day it would have gone in. It’s a tremendous save, actually. And then Tom got us out of there."

Roberts emerged for the post-match festivities with his best pal Kieran Tierney's jersey, not knowing that the left back, who sustained a facial injury after getting the wrong end of a swinging arm from Jayden Stockley, had been released from hospital in time to go up and lift the trophy himself.

"Kieran’s jaw wasn’t really up to talking," said Roberts. "But he was back there in the dressing room, enjoying the celebrations with all the lads. I’m glad he got there for that. I thought he was going to miss the trophy presentation, which was why I put his shirt on. I couldn’t see him around – but his ugly face popping up to cheer up the fans was some sight.

"I thought it was only right to get his shirt out, if he wasn’t going to make it, because the fans love him to bits. He’s Mr Celtic. When he did turn up, there was more anger than joy when he picked up the trophy, I think! I’m just delighted for him because he’s born into this club. To win a treble and go a whole season invincible at the club he supports, it’s massive to him. I just think he was angry because he couldn’t take part in the rest of the game. But we won the game – and he’s a part of that."