Following Chelseas damaging 2-1 defeat to Sunderland on Saturday, defender Marc Cucurella emphasised the teams urgent need to develop a killer instinct to close out games.
This latest loss at Stamford Bridge, secured by Chemsdine Talbis stoppage-time winner for Sunderland, means Enzo Marescas side has now squandered eight points from winning positions this season.
Chelsea had initially taken an early lead in the fourth minute via a goal from Alejandro Garnacho his first since joining the club from Manchester United, but Sunderland quickly equalised in the 22nd minute with a strike from Wilson Isidor. Despite dominating possession, the Blues failed to regain the lead, resulting in another frustrating performance.