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.
Goal for Liverpool.— West Ham United (@WestHamUtd) February 4, 2019
Mane scores from Milner's pass. Replays seem to suggest Milner was offside, but the linesman didn't raise his flag. #WHULIV 0-1 (22)
Lino not even looking at Milner for Liverpool’s goal, too busy admiring Lallana’s pass pic.twitter.com/wuxuNCWbtz— Ian Abrahams (Moose) (@BroadcastMoose) February 4, 2019
Linesman looking at Milner like pic.twitter.com/FvhWRX3yGg— Sam McGuire (@SamMcGuire90) February 4, 2019
Oh wow, Milner was only about 2 yards offside 😳😳😳— Footy Accumulators (@FootyAccums) February 4, 2019
Milner so clearly offside right in front of the linesman. Extraordinary miss by the assistant. 1-0 Liverpool.— Mark Pougatch (@markpougatch) February 4, 2019
James Milner was miles offside. This is beyond a joke now. pic.twitter.com/CPUqnIKBjN— DZ Football (@DZFootball_en) February 4, 2019
It's decisions like these that cost Titles Cups Relegation Manager's Jobs when are officials ever going to get this right?! ...You could park a bus between Milner and the West Ham back Line ! #shockingdecision #rollonVAR pic.twitter.com/iJhcG57VEP— Daz Davies (@davies_daz) February 4, 2019
It's borderline, but I think Shkodran Mustafi is playing James Milner onside in the run up to Mane's goal. pic.twitter.com/tYnnSEwh5n— Scott Rogers (@scottr0gers) February 4, 2019