For almost 20 minutes, Everton versus West Ham United was a tight clash that looked as though it could go either way. Passes were misplaced, the game was scrappy and neither side was able to progress up the pitch without an error halting their progress.
And then Joe Hart intervened, sliding out to chop down Dominic Calvert-Lewin and making the kind of error that relegation six-pointers are decided on.
From that point onwards, nothing went for West Ham. Manuel Lanzini was denied from the spot, and a second Hart error was punished by Wayne Rooney's stunning hat-trick strike.
Either side would have been hugely concerned had they lost this game, but it is particularly worrying for the Hammers who have made their big managerial call. While Sam Allardyce may drill Everton into shape, there has been no new managerial bounce for David Moyes.
With Manchester City, Chelsea and Arsenal up next, this was a game West Ham may well have needed to win and yet basic errors - the type that haunt a relegated team - were a constant throughout. West Ham face a real struggle this season without a stunning turn of events. The 4-0 drubbing at Everton may well turn out to be West Ham's most expensive defeat ever should relegation follow at the end of the season.