Roberts said: “It was good, a very positive performance. I know it’s only a point, but I thought we were unlucky not to get more.
“We gave a good account of ourselves in the group. We were disappointed after Monchengladbach away that we didn’t get the win there late on and on this occasion we’ve not managed to get a win, either.
“It’s frustrating, but we’ll learn and get better. Next season, Celtic will be much better equipped for the teams we play.
“It was a tough, tough group. We knew that from the start. We had to play our own way and try and get the best results possible.
“I think we have done ourselves proud in the group. We’ve finished with a really strong performance which is pleasing.
“Everyone wrote us off in the group, but we’ve shown our character against City at home and Gladbach away and here again.
“We’ve had a good group stage without winning a game, but it’s an extremely tough group. It’s the best tournament in football and we’ve done ourselves proud. We’ll be well equipped for next season.”
And he feels he left an indelible mark on the club which agreed to him spending 18 months developing his skills in Scotland.
“Every time I get on the pitch, that’s all I want to do. I don’t think about anything else, just my personal performance and the team I’m playing for.
“Whenever I get the chance to play, I try to do that and get goals and assists.”
‘He added: “Yes, I thought it was a penalty and a couple of the lads did, as well, but that’s football.