I'm pretty sure you're talking about Matthew Reilly's action series, though the exact title is 'Contest' or 'The Tournament'? Wait, no, 'The Unbeatables' is a kids' movie. There's a novelization of that, right? I think I remember a librarian friend mentioning it. The main guy is a washed-up foosball player, obviously. Then there's his young neighbor who's really into the game. And the villain is this arrogant champion who literally steals people's skills? Something like that. The girl who runs the gaming parlor is a key support. Honestly, the plot's a blur for me – it's more about the visual gags and the match sequences. If you're after deep character studies, this ain't it; they're pretty broad archetypes. But the dynamic between the grumpy mentor and the enthusiastic kid carries the heart of it, even if it's predictable.
For a book based on an animated film, it does a decent job expanding the internal monologues, especially for the lead. You get a better sense of why he's so bitter about his past glory. The villain remains pretty one-note, though, just a pompous obstacle to overcome. I'd say check it out if you loved the movie and want more of that world.