If the surprise early in this season was at how quickly a young Chelsea team had progressed under Enzo Maresca, then the concern now is of how slowly they seem to learn.
For the fourth time in a five-match winless run in the Premier League, the Blues were punished for failing to kill a game they had run, as a bare bones Bournemouth roared back from a goal down to lead 2-1 at Stamford Bridge.
