The NPD results for September 2020 showed that Super Mario 3D All-Stars debuted in the second spot on the charts, losing out to Marvel's Avengers. The thing is, when you take a closer look at the data, there's a much different story going on here.
First up, the data for Marvel's Avengers includes digital and physical sales combined. With Super Mario 3D All-Stars, the NPD position is based on physical sales only. That makes Mario's second place finish much more impressive overall!
Along with that, more specific NPD data has apparently leaked. That gives us some actual numbers to work with.
In the case of Super Mario 3D All-Stars, the total physical U.S. sales for September 2020 reportedly sit at around 1,165,000 units. The game managed to sell that total in about 2 weeks' worth of time. The previous record-holder for U.S. launch month sales goes to either Super Mario Galaxy (1,120,000 units in 3 weeks) or Super Mario Odyssey (1,100,000 units in 1 week), depending on how you want to look at things. Obviously digital sales were a factor for Odyssey and not Galaxy, and we don't have the data on how many digital units were sold.
Super Mario 3D All-Stars had a huge retail debut, but there's no doubt the digital numbers have been insane as well. The weekly charts showed the game sitting at the #1 position for every single week, so it was definitely pulling in big numbers. If we knew those digital numbers and could add them into the physical NPD total, there's very little doubt that Super Mario 3D All-Stars would be the new record-holder for a 3D Mario title when it comes to debut month sales.