This achievement along with the other one requires you to first unlock the two more difficulty’s from playing the career mode! So you can play the two difficulty’s on the multiplayer to unlock the two difficulties achievements for wining online in the championship make sure you put at least three races one lap is fine. Pistons= difficulty’s had some trouble figuring that out 🤦♀️ Happy hunting
Note: all you need is two players to do all the online achievements.
Just make sure you unlock the difficulty’s first