After opening the scoring inside 53 seconds, defender Martin Skrtel quickly scored a second goal with a fine header, before further strikes from Raheem Sterling and Daniel Sturridge emphasised the Reds' dominance.
Sterling added his second in the second half, with Arsenal's only reply coming from a Mikel Arteta penalty.
Here are the best tweets from a momentous day in this Premier League season:
Arsenal's Mesut Ozil started the day looking forward to the game, which would see his first ever appearance at Anfield. It was going to be one he'd remember...
Our man @gunnerblog was confident that Arsenal could impress at Anfield, but they were in trouble straight away and fell behind when Skrtel nudged in a Steven Gerrard free-kick. But was he offside?
Liverpool didn't care though, and as the Reds swarmed forward at will, it wasn't long before Skrtel doubled their lead with a fine header from Gerrard's corner.
The identity of Liverpool's unlikely goalscoring hero wasn't lost on many.
Whilst it was all a bit too much for some...
Liverpool were in no mood to show any sympathy though, and quickfire goals from Sterling and Sturridge turned their 2-0 lead into a stunning 4-0 advantage, as the Gunners were completely overrun.
And typically, the jokes soon started flowing at Arsenal's expense:
Liverpool were in no mood to stop the scoring though, and after the break, Sterling broke clear to score his second of the game, burying a shot past Wojciech Szczesny at the second attempt:
Arsenal finally had a moment to cheer when Arteta converted from the penalty spot, but it was undoubtedly Liverpool's day, and the jokes were about to flow once more:
Ultimately though, the final word went to two managers with extremely varying moods: