1) From main menu select SOLO --> QUICK RACE
2) Select a track where you like to race. I did it on Milford Street Circuit as this is the shortest track
3) Select mass start
4) Select 1 Round an continue
5) Select a Supersport bike
6) After the loading screen, adapt the difficulty settings. I set all driving assistants to high and shifting to automatic, also I changes general difficulty to easy
7) Start the race and win! Sure, this is the hardest part, but if you try not to hit the walls or other drivers from the side you should be fine. On easy you don't have to overtake all drivers in the first few corners, so drive safely and don't rush it, than you will win.
Winning the race will give you this achievement and
as well, as you only have to finish a race for that in SOLO mode, the mode were you just in.