- Randomly put the 25 cars into 5 groups, for 5 matches. Label each group.
(total: 5)
- Pick the top 1 of each group for another match. According to their rank, label them as a1, b1, c1, d1, and e1. Also label the rest of cars as a2, a3, b2, b3... Letter refers to the original group, number means their rank inside the group. (total: 5+1).
- For now we know that: a1 > b1 > c1 > d1 > e1. a1 is the confirmed fastest.
- Also: a1 > a2 > a3; b1 > b2 > b3; etc.
- Pick a2, a3, b1, b2, and c1 for another match. The top 2 are the second and third fast cars. (total: 5+1+1)

Total: 7