Chelsea manager Frank Lampard says his players have to make themselves heard and take more responsibility on the pitch as they chase a top-four finish to secure a Champions League spot.
Chelsea, who are third in the Premier League, lost 3-0 at Sheffield United on Saturday and Lampard said all he could hear were the opposition's voices in the empty stadium.
"When you talk about players, it's easy and natural to look at talent, but you also have to look at attitude and character within the team. It's something that we can improve," Lampard told reporters ahead of Tuesday's game against Norwich City.
"Younger players can be more vocal and can grow as they go along. Older players can take on the responsibility of helping that ... critical times like this where there's a lot on the line, it's time for people to make that improvement.
"The main thing is that you can be as quiet as you want off the pitch ... but they must come out of that on the pitch, they must demand the ball, otherwise the game can pass you by.
"... The important thing now is how we react and I expect that from the players," Lampard added.