And Bilic believes that level of performance is the standard they must hit if they want to secure Premier League football next season.

"When your side play like that it makes you proud. That performance has to be the standard going forward. We were better than them physically – we didn't just match them – and from there our quality made the difference," he said.

"Our guys showed spirit, character, effort and a willingness to win. We should have scored more goals, in the first half especially, but at this point the most important thing is the result.

"We were totally focused for 90 minutes. When you're like that you've got a chance to win. People said this was Millwall weather today, that the conditions would suit them more.

"But we're a team that fights, a team that gives everything. Millwall are always physical but they're playing good football under Gary (Rowett). We stopped them and neutralised them today through our work rate.

"This is a tough league and a lot of it is about momentum and confidence. The table matters, but not that much: your last results, attitude and the way your team starts games is crucial. It's demanding.

"The price is so big that it has to be tough. At the same time it's enjoyable. The Championship has those elements of football that are a little bit lost now: the smell of the grass, the fans shouting at you from behind the benches."

Defeat for Millwall leaves them five points off the play-offs and manager Gary Rowett insists they were outclassed by a superior side at The Den.

"A little bit of quality told today. When you play against sides like West Brom and Leeds you find that their extra bit of zip and composure makes it difficult for you," he said.

"I expected us to be more defensively resilient today. I can live with us not creating chances if we're solid at the back; we didn't do either today while West Brom delivered a very good performance.

"Their mentality in the conditions was fabulous. Given some of their play they could have been three or four up at half-time. There was a big gulf on the pitch today and a lot of it was down to our level of performance."