Mastery (Asphalt 8)

Introduced in the Hot Summer Update, Car Mastery (or just Mastery) is another single player game mode. It offers 15 single-lap races, called Challenges, for each car of the game, with the possibility to earn Credits, Car Upgrades, Boosters, and Licences.

Challenges
For each car in the game, there are 15 Races available, in increasing difficulty: the cars of your NPC opponents will be gradually increase from initial rank to max to max+pro. To be able to accept a challenge, i.e. take part in the race, you have to complete the previous challenges. Also your car has to have a certain level, the first 5 challenges being available without updates, increasing until Challenge 15 which requires a pro'ed car.

Rewards
For each race you play in the Car Mastery mode, you get a number of rewards. Similar to events, you can cash in those rewards after the race, or you can decide to leave them for later.

For each Challenge you get a Credits reward, and for Challenge 5, 6, 10 and 15 you get an additional reward amongst the following:
 * Tuning Kit
 * Nitro Starter
 * Class Upgrade
 * Licences

Licences
Licences work as an experience level, similar to the star system, which you cannot buy but only earn. However instead of giving you access to new levels, the licences give you access to new Decal packs, ans well as some cars apparently exclusively available through licences: Camaro Z/28 (300),  Datsun 280Z (650) and Shelby Cobra 427 (1050).