A ‘sloppy’ second half cost Chelsea all three points against Schalke 04 reckoned John Terry.
Klaas-Jan Huntelaar cancelled out Cesc Fabregas's opener and the Blues captain bemoaned a collective loss of concentration in the closing stages.
"We were pretty comfortable first half,” said Terry. “The second half, the manager (Jose Mourinho) kind of stressed that we can't get a little bit sloppy and throw it away, and that's exactly what he predicted," Terry told Sky Sports News.
"We've been killing teams off in the Premier League, but tonight, we didn't do that and we're disappointed to lose a goal on the counter.
"We've got some tough games coming up and I think in the second half, we were very slow."
Elsewhere in the group, Maribor drew 1-1 with Sporting Lisbon.
Chelsea will only be able to call on Diego Costa's talents for one game a week – says Jose Mourinho.
Blues had to line up with returning hero Didier Drogba for their 1-1 Champions League opener against Schalke, and had a frustrating night – failing to put away a series of chances.
Costa came on late for the Ivorian, but Mourinho says Blues simply cannot expect to have him ready for every single game.
“Diego Costa is not in condition to play three matches in a week," said the Blues' boss.
"He has problems when he plays one game, he needs a week to recover and now playing matches Tuesday and Wednesday he can't do it. He was not in a condition to do more than he did."
