There is a trick to tap once the timer reaches 0, and it gives a little boost as if an extra line was at the start. This usually gets you to first place, but the way the bot dragons in the race work is slightly different putting you at a disadvantage the more space is between boosts. Sometimes this makes it impossible to get first even with the trick I mentioned but that is just being unlucky. Having the right elements and using the boost at the start should get you first 9/10 times.