Liam Rosenior admitted Chelsea have a "deep-lying" issue after they fell to yet another defeat at the hands of Arsenal.
The Blues suffered a third loss to their London rivals since the beginning of the new year, this time succumbing to two set-piece goals from William Saliba and Jurrien Timber.
Rosenior's men did manage to score from a corner of their own; however, Pedro Neto's sending off, Chelsea's second in as many games, shut down any hope of a comeback against the league leaders.
"We conceded two goals from set-plays, which has ultimately cost us the game, and it’s really disappointing to have another red card," said the Blues manager.
"These are things we’ve spoken about, because there is a lot of good, but I don’t want to be sat here talking about how well we’ve played every week without picking up points.
*"It is disappointing for Pedro because he’s a very, very good player, and you want him on the pitch. Until that moment, he was actually causing Arsenal problems. The frustrating thing for us is that it’s not just today, but we’re going to miss him against Aston Villa."*
Chelsea have now had seven players sent off in the league this season, a worrying statistic for Rosenior.
"It’s a focus and concentration thing that we need to get right," he said.
"It’s not just Pedro, though. As a group, and me as the leader, we have to take more accountability for some of the decision-making in terms of our discipline.
"We had ten games from when I came in where we didn’t have these issues, but now we’ve had two red cards in two games, so there is something deep lying that we need to get to the bottom of.
"The thing is for me, if we can get to the bottom of those two main things, we can be a very, very good team and achieve all the things we want to achieve."