The Swede revealed many of his countrymen were less than impressed by Neil Lennon's side in the first leg of their play-off despite the visitors to Helsingborg emerging with a 2-0 lead that they doubled in the return at Parkhead.
The Scottish champions went on to qualify from Group G as runners-up to Barcelona following an impressive campaign which included a famous win over the Catalan giants, and are now looking forward to next Thursday's last-16 draw.
Lustig, who is hoping to see Celtic paired with boyhood favourites Juventus, was at Celtic Park to preview tomorrow's Clydesdale Bank Premier League clash with St Mirren but he looked back with satisfaction at the way the club's European sceptics had been silenced.
He said: "(The reaction in Sweden to us qualifying) has been quite massive.
"When we reached the Champions League a lot of the media in Sweden said that Celtic is probably the team that shouldn't be in the Champions League because they saw the first leg against Helsingborg and they weren't much impressed with that.
"Over two legs I think we were the stronger team but the first half in Helsingborg was really bad.
"Now they have seen that we are a really good team and work good together."
Asked about his childhood passion for Juve, the 26-year-old full-back added: "I was a big Juventus fan when I was growing up but I don't know why. I don't think they are going to win the Champions League but they are obviously the best team in Italy right now and they should be disappointed if they don't reach the semi-final.
"We are going to be underdogs whoever we get, although on paper Malaga could be a good draw for us. We were probably underdogs in every group game and we handled that pressure quite well."