Evenly matched? Not quite, and considering this was TOEI-filler junk they had to spice things up beyond madness because we're looking at our friend Goku. Goku was only capable of SS (or "FPSS") at the time and yet he was able to keep up with Pikkon's movement, where hours earlier Pikkon dispatched Perfect Cell with one blow. On earth, Goku admitted he was weaker than Perfect Cell (not to be confused with S. Perfect Cell), and since the Zenkai was practically removed from the story you can't credit Goku with it. Inconsistency? Anime plotholes? Filler? Yes, more, and it was pretty big.
As far as I remember Yamcha never fought Pikkon, and if he had it was sparring - plus, Yamcha, throughout the entire series, was never capable of defeating Cell, and even the androids. No amount of training could've fixed that, I'm afraid. Don't get your hopes up.
To everyone saying "Any future character can win, da-de-da..." You're not making a point, and it's so amazing how narrow that concept is. Okay, so Super Saiyan Trunks could take out Frieza. So what, any Super Saiyan could've. But, I can prove you wrong on a number of things; Supreme Kai was a "future" character and he couldn't have beaten Perfect Cell, unfortunately. Let's see, Dabura? Perfect Cell was also stronger than him. Um, there are plenty of comparisons that'd prove to be worth a watch, but I'm merely pointing out obvious and useless things, like Supreme Kai being ground to a pulp by Cell, or SS Goten & SS Trunks being owned by SS Goku (Cell Games) simultaneously. In the process though, I'm pointing out half of your theory, I suppose I can even call it that, is practically a waste of words.
It's too bad you never actually see these fights. They'd be interesting, regardless of how short they would be.
