BBC Sport https://www.bbc.co.uk/sport/av/football/63610593 https://ichef.bbci.co.uk/live-experience/cps/240/cpsprodpb/1153B/production/_127617907_p0dftklk.jpg Chelsea head coach Graham Potter says his side "lacked quality" and that their busy schedule "took its toll" during their "tough" 1-0 defeat…