Can be done during the two hour free trial.
From Main Menu, choose New Game to begin Season One. Select the second race (Straight Race or something like that), and complete it. This takes about a minute or so to complete. Once done, select Next to go to the next race scene for the race to register as one count. Instead of going to the next race, go back to the Main Menu, and select the same race again.
Rinse and repeat until it unlocks. If you're fast enough, you can also use this method to unlock the rest of the "complete X number of races" and "win x number of races" achievements.
Tips to win:
- during the start, try to align the top and bottom lines together to get a headstart
- press
repeatedly to gallop
- press
to whip when it's available (do not over-whip as the horse will stop running)
That's about it.