Slaven Bilic says his West Ham United side "executed the game plan almost perfectly" as they came out 2-1 winners against a Chelsea team who have "hit great form recently."
A great night, insists Bilic
The home side took the lead from a strong Cheikou Kouyate header in the 11th minute, with summer signing Edimilson Fernandes doubling the lead just after half-time with his first goal for the club.
Chelsea's Gary Cahill pulled one back late in the game, but West Ham managed to hold on and are consequently through to the last eight of the competition.
"We played really good tonight, it was a great atmosphere, night game, cup game, London Derby," Bilic told whufc.com.
"We were great in the first half, really good in the second half. When we had to defend we defended with numbers, we were good at keeping the ball."
He continued: "We scored two, could have scored more, should have scored more, but it's a great win. It was a great performance because otherwise it is impossible to beat Chelsea."
Focus on Fernandes
It was West Ham's Fernandes who particularly impressed Bilic. The Croatian said: "He is very young, relatively unknown in England."
Bilic admitted that he did not think the Swiss Under-21 international would break into the first team so quickly.
"He is a very talented player who has to continue to work hard," said Bilic, before adding: "He's got everything; he has great stamina, great technique, great skill, a good football brain."
This win makes it three in a row for West Ham as they look to put their early season troubles behind them. They will now face Manchester United at Old Trafford in the quarter finals.