Confidence was high in Bilic's side ahead of the visit of Pep Guardiola's side with two consecutive league victories, but they were taught a lesson by the Spaniard's side.
Goals from Kevin De Bruyne, David Silva, Gabriel Jesus and a second-half penalty from Yaya Toure rounded off an excellent performance, and Bilic shared his stress about his side's performances.
“We can say that it’s playing Man City and not every team is like Man City," Bilic told whufc.com. "That’s true but we have to get over this game and we have to prepare for the game against Southampton."
“They beat us 5-0 in the cup and then 4-0 tonight and make no mistake," he stated. "We have to give them credit but it was also about us."
"We gave those kinds of players too much space and time on the ball and space between the lines," the coach stressed. "When you give them space like that they just slaughter you."
“It was very frustrating and it’s like what happened in the cup," the Croatian admitted. "We again started well."
"But when you make mistakes like we did," he affirmed. "For some of their goals and if you give the ball away in those areas then they punish you."
Bilic added. "After that, it’s very difficult to play against them.”
Looking to bounce back
The Hammers will be handed a golden opportunity to bounce back from another heavy defeat with a trip to Southampton, and Bilic is confident that a good opportunity stands ahead of them at the St Mary's Stadium.
"It's a heavy defeat for us but after every one of them we bounce back," he said. "After the Arsenal defeat, we bounced back, after the City defeat in the cup we bounced back. We have to do it now."
"The good thing about football is that there is an opportunity in three days' time," the 48-year-old stressed. "We cannot say it doesn't matter and let's forget about it."
"But on the other hand," Bilic concluded. "We cannot let this affect our game and everything good that we have done recently."
West Ham United will take on Southampton at St Mary's Stadium on Saturday, February 4 with kick-off at 3pm GMT.