This is a comparison (as objective as possible, using visual evidence) of the overall fighting abilities of Spider-Man and Mr. Popo, and the likelyhood of which one can come out on the better standing (iow, who "takes a licking" and who "keeps on ticking"). No specific setting or situation, other than that the two have chosen to fight eachother.

Spider-Man is as we all know him. Super-strength, super-speed, spidey sense, radioactive spider-blood, the whole shabang. I'm not terribly familliar with examples of his min/max capabilites from the comic, so let's discuss Movie Spider-Man first and then downgrade/upgrade to Comic Spidey afterwards.

And here is Mr. Popo. I'm assuming not too many know who this is, so I'll start things off with a few examples. Basically, Mr Popo is Kami's blackface genie from Dragonball and Dragonball Z.
He may not look like much and doesn't participate in a lot of battles, but keep in mind he took direct part in training several of the 'Z fighters' in preparation for taking on Vegeta and Nappa in the Sayajin Saga. And much later on (in the Buu Saga), he easilly defended the attacks from Super-Saiyajin Goten and Trunks at the same time. These are better blocking abilities than Vegeta, who actually failed to block one of Trunks' punches when training one on one with him not long before the Trunks & Goten vs Mr. Popo incident.

It'd be almost impossible to determine an upper limit for Mr. Popo's fighting abilities from his few examples of combat, but it's a start for determining what he can do at the least.
Well, take it from here. I'll see if I have any observations or facts to interject in a while.