After West Ham beat Liverpool in extra-time in the FA Cup this week, manager Slaven Bilic declared the result as one of the greatest night's in the club's history at Upton Park, Talksport reported.
This weekend they are on their travels, and pundit Paul Merson predicts they will come crashing down to earth with a bang.
He believes it is all down to timing, expecting West Ham's players to be exhausted from their exploits in midweek, calling a 2-1 win for the Canaries.
He explained: "This game is another prime example of how the timing of football matches can affect the outcome. Norwich will have looked at the fixtures and probably wouldn't have fancied themselves against a West Ham side that has been flying this season.
"However, when you consider the Hammers played 120 minutes in midweek, have an eye on the next round of the cup and probably can't qualify for the top four, then this the best time ever to play them. West Ham have got a great chance to win the FA Cup and have bigger fish to fry so I fancy Norwich to nick a vital win."
The important factor Merson does not take into account is confidence. West Ham will be full of themselves after winning against Liverpool. Lose the game in similar circumstances and it will have felt like they played 500 minutes instead of 120, but with the feel good factor of star man Dimitri Payet signing a new deal, the Hammers are flying.
Norwich on the other hand are sinking. They sit in the relegation zone and have lost their last five games in a row. Even a draw would feel like progress.