DSi has become the fourth fastest-selling console in UK history.
Opening weekend sales were behind those of PSP, PS3 and Wii, but ahead of all other platforms, according to stat cruncher GfK-ChartTrack.
The portable's sales exceeded those of all other consoles combined over the weekend.
"It's a very impressive opening couple of days considering the lack of launch software," GfK-ChartTrack's Chris Poole told MCV.
"It's difficult to tell if the momentum will continue into the week, as much of the sales would have been pre-ordered. There was also a slight spike in DS software."
This news comes on the back of strongly worded comments from SCEA director of hardware marketing, John Koller, who criticised Nintendo for ignoring "significant gamer demographic groups" by releasing another product supposedly just for kids.