Mario Kart

Ok so I'm so sick of playing against Sergio in Mario Kart! I used to be the best player ever!! Sergio used to could never beat me and now he beats me like 8 out of 10 times!! Talk about frustrating!!! I mean I am now getting better because we've been playing so much but even when we tie with points in the end the game always picks Sergio as the winner. So I'm convinced the game is rigged. Wii is now my enemy.