This paper considers the autonomous racing of three cars, including a team of two cars and an opponent car. To handle it, the competition is modeled as a two-leader one-follower Stackelberg game to obtain the optimal strategies for each car. In the sequential game, all the cars maximise their progress while avoiding collisions. In the blocking game, blocking behaviours are taken into account by adding a reward to the payoff function. Through successful collaboration, actions are more aggressive in the second game. Given that the Stackelberg equilibrium is not unique in both games, the cost functions are designed for the players to cope with multiple strategies that have the same progress. The competitions are performed in a receding horizon fashion, and the aim of the research is to study the effects of cooperation and make the team have successful blocking behaviours under constraints as well as speed disadvantages.