The Blues had twice taken the lead through Costa and Nemanja Matic in the first half, but Sam Allardyce’s men fought back valiantly at the Stadium of Light.
Wahbi Khazri scored a stunning equaliser before Fabio Borini and Jermain Defoe turned the game on its head in the second period.
The defeat at Sunderland was just the latest one in Chelsea’s poor recent run of form. Hiddink’s side have won just two of their last eight top-flight games, losing three of them, and the Blues interim manager wasn’t afraid to criticize one of his players in particular following the latest defeat on Wearside.
“For them [Sunderland] it felt like that [they had a 12th man with crowd],” the Dutchman said, as reported by Goal. “It was not hostile, it was very enthusiastic but my players are experienced in that and they should have coped.
“Yes, I think that is maybe the difference [Costa’s casual finishing]. They desperately wanted this game and maybe we are a little bit too relaxed.
“In normal very, very tight situations he is used to scoring. He took too much time and when you take too much time they start thinking [they can win] then the moment is over.”
In what’s been a strange season for the Premier League champions, and especially for Costa who has ound it tough to replicate his form from last season. The 27-year-old has scored 12 goals and created 30 chances in 28 Premier League appearances, with a shot accuracy of 53% and an average pass accuracy of 78%.
Saturday’s result left the Blues ninth on 48 points, 17 adrift of the top four with just two games remaining. That Hiddink was unable to turn around the side after Jose Mourinho was fired, indicates that the troubles at Stamford Bridge go a lot further than the manager.
Next up for them is an away clash at Liverpool on Wednesday night, before their final game of the season at home to newly crowned champions Leicester City on Sunday afternoon.