Brendan Rodgers admitted Celtic have a lot to learn after a 7-0 humbling at the hands of Barcelona on their first match back in the Champions League after a three-year absence.
 Lionel Messi scored a hat-trick, Luis Suarez twice and Neymar added a fine free-kick to his four assists as Barca’s stellar ‘MSN’ frontline enjoyed their reunion on their first start together for four months.
 “Professionally it is never nice when this happens,” said Rodgers after Celtic’s record European defeat. “You are trying to keep the lines tight, but the ball moves like it is on an ice rink. They moved as fast as that added to a high level, big confidence and big belief.
 “This is going to be a brilliant learning season for us in the Champions League. There can be no embarrassment because they do that to better teams than ourselves.”
 Defeat was an even more sobering experience for Celtic coming hard on the back of thrashing fierce rivals Rangers 5-1 on Saturday.
 And Rodgers argued the short turnaround between the games contributed to Celtic’s demolition with five of Barca’s goals arriving after half-time.
 “Whenever you lose as a professional with so many goals it is tough to take, but these players have been brilliant since I came to the club. To come here they couldn’t have come to a more difficult place in world football after such an intense game at the weekend. To have so little preparation time to come here was a tough task and that last 15-20 minutes seemed quite long.”
 Rodgers hailed Suarez as the world’s best striker before the game, having spent two years with the Uruguayan at Liverpool. Suarez scored 31 goals as Rodgers nearly ended Liverpool’s two-decade drought without a Premier League title in 2014, but admitted it was tough to be on the receiving end of his brilliance.
 “The framework of the team is strong, it is lit up by the front three and Luis is the spearhead of that. When you are on the other end of it, it is not so nice,” he said.
 Barca, by contrast, suffered a shock 2-1 home defeat to Alaves at the weekend. “We are human and we can have a bad day. It can happen to anyone,” said Suarez.
 And, Andres Iniesta, who scored the hosts’ other goal of the night with a sumptuous volley from the edge of the area, recognised they had taken their frustration out on Celtic.
 “We came off a defeat that hurt us a lot for the way in which it came about but there is always an opportunity to quickly change that image, those sensations in the next games and today the team did that from the first minute,” said Iniesta. “We very efficient and created a lot of chances.”
 Messi’s hat-trick was the 36th of his Barca career and a record sixth in the Champions League. “It is difficult to say anything about him which hasn’t been said,” added Iniesta. “In every game he surprises you with new things. There is only one Leo, he is unique.”