Earn a total of 1,000,000 Cr from Rivals.-10G

Each time you set a time in an event you will be asked if you want to compete against a rival to see if you can beat their time. Each time you do beat the target time you will receive a sum of credits and be asked if you want to try for a faster time. There is also a tab in the menu for rivals where the game will constantly add possible rivals for you to beat. This is often an easier approach as you can select your car and some cars are better suited for certain events such as using an AWD car for an off-road event. Depending on your skill you should be able to earn an average of 8,000 to 10,000 credits per rivals event, significantly more if you are better at the game, so reaching one million shouldnt take too long.

It's also worth noting that you don't need to beat your rival to collect credits. You can still finish over time and earn a decent amount of credits.