He could be huffy and defensive here. That it was just an undignified noise. That it wasn't much of anything at all. He was just moderately amused, that's all. But it's nice to see Riz so proud of himself, actually.

Especially after the race ended as it did.

So the huff is entirely for show, no real feeling in it. "Oh very well, you did, didn't you? There's no hiding from such deductions."