Here's another early UPA short, the John Hubley directed "Fuddy Duddy Buddy". The opening scene of Magoo trying to convince Bottomley to play tennis is really well animated. I'm not sure but I think Pat Matthews animated the scene where the walrus charges the net during the game of tennis. I think the following shot of Magoo might also be Matthews but I'm not too sure. Of course, Paul Julian's backgrounds are great too.
Check out The Big Blog of Kid's Comics! for a comic adaptation of the cartoon drawn by Dan Gormley