Juventus midfielder Miralem Pjanic urged his team-mates to remain calm after Lionel Messi inspired a 3-0 win for Barcelona in the Champions League Group D opener.
Pjanic was to the fore as Juve matched opponents they vanquished in last season's quarter-finals for much of the first half, but Messi's magnificent opener on the stroke of half-time changed the complexion of the contest.
The mercurial Argentinian created Ivan Rakitic's second before sublimely completing the scoring, but Pjanic believes an injury-hit Juve should retain a sense of perspective.
"We really didn't have to concede that goal because the first half was almost over," he said, as quoted by UEFA.com.
"We played well in the first half and I think we could have scored.
"In the second half we did not play as well, but it was just the first game and we don't need to panic.
"We were missing several players, but this is not an excuse, we just need to learn the lesson and continue working as we are doing.
"We have time to recover from this defeat."
Juve will aim to preserve their 100 per cent start in Serie A when they travel to Sassuolo this weekend and Allegri's team resume Champions League action at home to Olympiacos at the end of this month.