It comfortably beat the previous holder of the UK’s bestselling new IP, 2011’s LA Noire, beating its first week sales by 58%, according to Chart Track.
Not only that, but Watch Dogs has also become Ubisoft’s best ever game launch in the UK, selling 17% more than 2012’s Assassin’s Creed III.
Finally, the hackathon is able to break into the UK’s Top 20 best ever launch weeks, entering at 17th. The game is only beaten by entries into the GTA, Call of Duty, FIFA and Battlefield franchises.
The PS4 version was the dominant force for the game, and helps the PS4’s hardware sales to rise by 94% this week.
Mario Kart 8 also had a very impressive launch this week. It eases into second with the best week one sales the Wii U has produced. The title also achieves the second best first week sales of any game in the Mario Kart series.
Along with Watch Dogs, Mario Kart gave hardware sales a massive boost with the Wii U sales up a whopping 666%, 82% of which being the new Mario Kart 8 bundle.
Elsewhere in the charts, Wolfenstein: The New Order makes way for the top two and finds its way down to third, and FIFA 14 slips a place down to fourth.
Minecraft: PS3 Edition falls three places into fifth and 2014 FIFA World Cup Brazil finds itself in sixth.
TItanfall drops down to seventh this week and Minecraft: Xbox 360 Edition comes in eighth.
Call of Duty: Ghosts falls down to ninth whilst The LEGO Movie Videogame holds firm at 10th.
Elsewhere in the charts sees Borderlands 2 re-enter the charts in 18th, following the release of the PS Vita version.
The UK All Formats Chart Top 10 (Week ending 31st May 2014) is as follows:
1. (N) Watch Dogs
2. (N) Mario Kart 8
3. (1) Wolfenstein: The New Order
4. (3) FIFA 14
5. (2) Minecraft: PS3 Edition
6. (5) 2014 FIFA World Cup Brazil
7. (4) Titanfall
8. (7) Minecraft: Xbox 360 Edition
9. (6) Call of Duty: Ghosts
10. (-) The LEGO Movie Videogame
You can see the full Top 40 here.
Next week sees Murdered: Soul Suspect released. Whilst it will be expected to chart, I doubt it will knock Watch Dogs off the top.