Chelsea defender Gary Cahill has admitted that he cannot pinpoint a reason for the Blues' poor form in the past six weeks.
The Champions League holders have gone seven games without a win in the Premier League and now trail leaders Manchester United by 10 points.
Rafael Benitez earned his first win as Chelsea boss in midweek with a 6-1 thrashing of Nordsjaelland, which was ultimately not enough to save their title defence.
Cahill believes that hard work on the training ground will help the Blues bounce back.
He said: "I don't know what's gone wrong. That's the honest answer. It's the same group of players.
"The players have been asking that question themselves and we don't know really. Where do you point the finger? It's obviously stuff you need to work on in the training ground.
"It's the same group of players who started the season beating teams and scoring goals and keeping clean sheets. There's no reason why we can't get back to that, but we were hoping it would come sooner."
Chelsea are aiming to earn their first league win since Benitez took charge when they face Sunderland this weekend.
