Chelsea progressed to the quarter-finals of the Carabao Cup after a hard-fought 3-2 win over Championship side Derby County.

Chelsea legend and assistant manager Gianfranco Zola criticized the performance of Andreas Christensen and Gary Cahill against Derby County.

Chelsea looked vulnerable at the back against Derby County with our centre-back pairing of Cahill and Christensen failing to impose themselves.

“Gary played for the first time in a while,” Zola said.

“When we didn’t defend well, it wasn’t just the defenders.

“I thought Gary and Christensen could have done better with the ball in the first half.

“This is probably the complaint, but we will go through this and discuss this [with them].”

Zola also revealed Chelsea’s passing against Derby County wasn’t sharp and believes our performance against Derby was shaky.

On Chelsea’s performance against Derby, Zola said: “It was more than a bit shaky, but that was down to Derby.

“They played with a lot of quality, but our passing wasn’t sharp and in the last 15 minutes we lost a bit of control.

“Some things didn’t work well, some did.”