The New Zealand Indy Car driver, Scott Dixon, has scored a controversial victory in the latest round in Edmonton.
Dixon was in second place heading into the final lap, behind Brazil's Helio Castroneves, with the overall leader, Australian Will Power, in third.
But heading into the finish Castroneves blocked team-mate Power, and stewards decided to penalise him, demoting him from first to 10th.
Castroneves was clearly frustrated with the decision, and yelled at the race officials immediately after the race.
Power, who finished in second place, says he felt he was cut off.
The Australian retains the championship lead, while Dixon stays third overall behind Scotland's Dario Franchitti.