Not a surprise really. Most predicted this will happen, especially in the UK. Spider Man will most likely have a better launch WW as well. The question is will it stay that way by the end of the year and the answer is no. Mario will outsell Spidey during the holidays. Launch - Spider Man, Short term - Mario, Lifetime - ???
Most likely lifetime will go to Spider man if we assume that it will be ported to PC and go through multiple price cuts. That's something Mario Wonder won't have, however it could be close depending on Nintendo's next console.