If you want an alternative to setting up races there is actually a fast way to get it done. Head to head races against players count towards this as long as you win, or are close enough to cross the line near the other player. Just drive up behind them and follow the prompt to start the race.
I managed this by searching for co-op campaign lobbies and challenging people until I got it. It's a decent option if you don't have another player to team up with.
Good luck!