Naruto is actually more in his physical prime than Shodaime would be had he lived a full life (assuming he didn't as every appearance we've seen him in has been roughly the same age).
We don't know if Madara purposely did that to get his cells. Likewise, we cannot forget that Mito also stepped in and sealed the Kyuubi in herself in the heat of battle.
Madara could be lying, let's find out more details about this battle.
Anyway, as it stands now, Naruto would win because we know too little about Shodaime.