1. Freud regarded the subconscious shown in his dream as sexual desire.
Racing should be a strong sexual desire, and the opponent is the competition between sex and love. Bicycles, U-shaped hutongs and toilets are all relevant considerations.
2. General understanding
You may be an energetic and competitive person. Have a sense of superiority, want to compete with a strong opponent, but worried.
3. Dreams are just an illogical and disorderly combination of the subconscious. Play a game. Besides, it makes no sense.