The former Arsenal midfielder turned pundit feels Brendan Rodgers' men face an even huger occasion than usual against Manchester United this weekend as a result.
But, in terms of the Hammers, the 47-year-old says he was simply taken aback by their 3-0 victory at Anfield.
"I thought they’d bought well with James Milner, have a good player there already in Philippe Coutinho and got someone in Christian Benteke who is always a handful.
"I saw them against Arsenal and they ripped them apart in the first half. But then they got slaughtered by West Ham. It was very strange."
As historic as West Ham's Anfield win was, then, some may joke it's even more historic that Merson hasn't been able to criticise the Hammers as a result.
Obviously, the east London side's home form is still an issue for Slaven Bilic's men - and they will need to put that right against Newcastle United on Monday night.
As for Liverpool, though, the pressure is on. Right now, it's looking like the same thing year after year after year - with a Luis Suarez goalfest sandwiched somewhere in the middle.
Manchester United host the Reds in Saturday's evening kick-off.