Given that Watto is a Toydarian, I'd say it's pretty likely he's referring to the Human race. In general, human's aren't capable of the skill / speed /reflexes needed, so Anakin managing to perform to that level is something he gives credit to. Also, he's addressing Qui-gon; another human.
Add the line before the one you quoted, and it's more visible:
('Your' is addressed to Qui-gon, referring to his (the Human) race.)
QUI-GON : You don't think Anakin will win?
WATTO : Don't get me wrongo. I have great faith in the boy. He's a credit to
your race, but Sebulba there is going to win, I think.
See the entry on Wookiepedia for Pod Racing
A relevant quote:
Because of the reflexes needed to control the pod as it raced around the course at breakneck speeds, as well as the dexterity needed to control the pod racer, all pod racers (apart from Anakin Skywalker) were nonhumans. Inhuman physical attributes, as well as extra pairs of hands, came in handy when trying to control the pod at its top speed of around 900 km/h.