Liverpool fans would have been as delighted with their 2-0 win on Thursday night as Manchester United fans devastated.
But West Ham United supporters would also have reacted positively. Indeed, if United played like that during a huge clash against their fierce rivals at Anfield... just how badly will they play against the Hammers on Sunday afternoon?
Indeed, West Ham will now fancy their chances of getting past Man United at Old Trafford more than ever.
United were poor and lifeless. Fans just couldn't believe what they were seeing. The form West Ham are in, meanwhile, they can most certainly capitalise.
Aston Villa, however, may have come in for yet more bad luck. Indeed, their opposition this weekend lost 3-0 in Europe - making them extra motivated to bounce back.
But that isn't the main reason Villa should be worried. Mauricio Pochettino rested the majority of his first team against Borussia Dortmund, emphasising the fact the Premier League is his priority.
That means the likes of Harry Kane and more will be refreshed and ready to give Aston Villa the runaround on Sunday afternoon.
And there's also the small coincidental fact that Manchester City had also lost 3-0 in their last game... before beating Aston Villa 4-0.