The episode, entitled The Long Night, saw the Battle of Winterfell finally take place in some climactic combat scenes.
The mammoth instalment of Game of Thrones saw 17.8million viewers tune in, according to the Mail Online.
The record-breaking number includes figures from HBO Go as well as HBO Now.
However, it also currently holds a 75 percent rating on review site Rotten Tomatoes on reviews provided by critics.
It is the second lowest score an episode has received after season five episode Unbowed, Unbent, Unbroken which holds 54 percent on the respected site.
The episode has attracted some complaints from viewers over how dark the scenes were.
The battle took place at night and so much of the action was illuminated by fire.
Many took to Twitter to express their frustration over the lack of visibility on screen.
One fan wrote: “I know the night is dark and full of terrors, but can we make the episode visible at least?”
“This episode of Game of Thrones is dark. And not in a good way. I literally can’t see what’s going on,” another added.
“This show is so dark my eyes are filling in the blanks in 30% of this episode,” a third shared.
While a fourth opined: “Was really looking forward to this episode of Game of Thrones but it’s pointless. So dark, don’t know who is who. Someone was saving on electric that day.”
The instalment saw the Night King (played by Vladimir Furdik) slain by Arya Stark (Maisie Williams) as she suddenly attacked him, seemingly, out of nowhere.
The leader had been lured toward Bran Stark (Isaac Hempstead Wright) as Arya pierced him with her Valyrian sword, leaving him and the rest of the undead to shatter into pieces.
Although some fans weren’t happy with what went on and think there must be more to come from the Night King.
As one Redditor wrote: “This was truly an amazing episode and the director did a fantasic job on the battle. But.. they hyped up The Night King for seasons upon seasons, years upon years and this is how he goes out? There’s just no way.
“This plot is so stupid. I think there’s more going on then what meets the eye. Why else was Bran warged for so long? Could it be going back in time to prevent all this bloodshed? Could he have been making a deal with The Night King?
“When The Night King walked up to Bran, he looked like he accepted his fate. I just feel like The Night King is Bran, The Night King was going to kill Bran to destroy himself.
“I mean the way The Night King just looked at Bran, it felt like he had to do it when he didn’t want to. Arya ruined the plans for Bran.
“After all this and then they’re already going to battle with Cersei? Something just doesn’t feel right.”
But viewers will have to wait and see what season eight episode four brings.
Game of Thrones continues Sunday on HBO in the USA and the following day on Sky Atlantic and NOW TV in the UK.
