The game managed to smash the week one sales of last weeks’ number one; Assassin’s Creed: Syndicate, with Guardians managing to beat its first week sales by 50%, according to Chart Track.
It is also the same figure that Halo 5 beat last years’ Halo: The Master Chief Collection, the only other Halo game released on Xbox One.
This entry means Assassin’s Creed: Syndicate drops down one place to second, with FIFA 16 also down one spot to third.
WWE 2K16 enters the charts in fourth, beating the week one sales of last years’ WWE 2K15 by three to one.
Another new release in in fifth this week, with the physical release of Minecraft: Story Mode, which comes loaded with the first episode and access for the others when they are made available.
Grand Theft Auto V is down one place to sixth, as Uncharted: The Nathan Drake Collection drops three places into seventh.
Watch Dogs finds itself back in the Top 10, up four places into eighth, as LEGO Dimensions falls three places to ninth.
The Top 10 is rounded off this week by LEGO Jurassic World, which falls one spot.
Elsewhere in the charts, Guitar Hero Live suffers a big drop, down to 11th this week from its third place last week.
The only other new release this week is the Xbox One and PS4 versions of last years’ PC game Divinity: Original Sin, Divinity Original Sin: Enhanced Edition, which enters the charts in 37th place.
The UK All Formats Chart Top 10 (Week ending 31st October 2015) is as follows:
1. (N) Halo 5: Guardians
2. (1) Assassin’s Creed: Syndicate
3. (2) FIFA 16
4. (N) WWE 2K16
5. (N) Minecraft: Story Mode
6. (5) Grand Theft Auto V
7. (4) Uncharted: The Nathan Drake Collection
8. (12) Watch Dogs
9. (6) LEGO Dimensions
10. (9) LEGO Jurassic World
You can view the full Top 40 here.
Next week we have Call of Duty: Black Ops 3 enter the charts, which should claim first position. It will be interesting to see how Halo 5 will cope in the next few weeks, with some big hitters along the way.