Liverpool struck first in their trip to London to face West Ham, but the Anfield outfit can count themselves lucky to have done so after the linesman missed James Milner receiving a pass from an offside position.
Adam Lallana flicked a ball into the path of Milner, who found Sadio Mane to score Liverpool's opener in the 22nd minute.
It is a goal that could prove instrumental in the Premier League title race, as Liverpool entered play just two points ahead of second-placed Mancester City, but is also a goal that should not have stood.
Replays showed Milner was well offside when Lallana made the flick to him, which meant the goal should have been ruled out.
However, the linesman did not appear to be looking at Milner, instead following the ball, and allowing the makeshift right-back to get away with what seemed like an obvious call.
It is something that will likely not happen next season when the Premier League institutes VAR, but that will come too late for West Ham on this day.
However, West Ham did manage to equalise six minutes later through a superbly exectured set-play which freed up Michail Antonio to slot home off the post.
The linesman also had a bit of a miss later on, as he ruled Mohamed Salah offside during an attack when the Liverpool star appeared to be well on.
But while the linesman may be missing calls, Twitter did not, showing no mercy after the goal that should not have stood.