>>55853387Grind on Oreburgh Gate and the Oreburgh Mine. Evolve Chimchar into Monferno and you're good to go for the rest of the game.
Mach Punch and Close Combat are priority moves while Infernape himself outspeeds half the region, you won't have a problem unless you let some dumb shit slip, like trying to outspeed Maylene's Lucario or letting Candice set up her Frosslass. Sinnoh starters are phenomenal, all of the three are viable. It's all a matter of paying attention.