Brendan Rodgers says Rosenborg's 1-0 win over Ajax illustrates the progress his Celtic side have made in Europe.
Rodgers' side knocked the Norwegians out of Champions League qualifying this season courtesy of a 1-0 away victory.
"You only need to look at Rosenborg's result last night away to Ajax [in Europa League qualifying]," he said.
"It really demonstrated the level of our performance when we played out there - Ajax were in the Europa League final last year."
Having drawn 0-0 with Rosenborg in Glasgow, setting up a tricky trip to Norway, Celtic produced a mature second-leg performance to run out winners courtesy of James Forrest's strike.
'It's about continual development'
That set up a play-off meeting with Astana and Celtic's 5-0 win on Wednesday all but booked their group stage berth ahead of Tuesday's return leg in Kazakhstan.
Last term the Scottish champions drew three and lost three of their Champions League group stage matches, after being drawn with Barcelona, Manchester City and Borussia Moenchengladbach.
And Rodgers is happy that his charges are making significant strides as they stand on the brink of another campaign in Europe's elite competition.
"We still have a way to go but what's important for me as the manager, and the coaches, is that we're seeing improvement," he added. "If you think of our last games away from home in the Champions League, we've performed to a really high level.
"It's about continual development, it's about having that hunger and continuous drive to succeed and be better, and this group of players has that. I would expect us to go on this year and continue to improve.
"But if you're saying can we match Barcelona, Bayern Munich, Real Madrid, then it's very tough. The financial difference now is absolutely huge.
"We'll always be competitive, but I'm also a realist. You're not going to be sat there writing about us winning the Champions League, that's for sure, but our aim is to compete and to develop our players and our game over the coming seasons. If we can do that at the highest level in Europe, that's what we aim to do."
Goalkeeper Craig Gordon agrees with his manager that Celtic are improving on the European stage.
"I think it comes from knowing the way we want to play from having an organisation and knowledge of our tactics," Gordon said. "We've obviously worked on it for a year and the manager's continuously working on that with us.
"We've come back from setbacks and still won games so we're confident that no matter the situation or scenario we've got the player and teammate round about us that can pull us out of anything."