You won a career event on the hardest difficulty without using Flashbacks.
It is recommended that you do this on the first race available to you in the career. Go to "Options & Extras" and change the difficulty to "Very Hard". Use the timeline to select the "California Race - Pacific Way" in the first club series, and choose the Chevrolet Camaro Z28, as it is the fastest. You should be able to do most of the race without braking, and you will naturally overtake the opponents in the turns because of your car. Make sure that you don't use any flashbacks, and if you do happen to crash, you'll want to pause and restart the race until you win.
I can't get this either, I'm not sure if it's because I'm playing a career event from the timeline, or because I'm choosing to restart in the race if I mess up...I mean it's not a flashback but maybe (mistakenly) it counts?
Ok I had to read up elsewhere to do this, as I tried doing an Overtake event in the career on Very Hard without restarts or flashbacks and it still didn't pop. If you go to the timeline, season 1 and re-play the first race in California (California Race, Pacific Way) use the Chevrolet Camaro Z28, then just go for the win. You don't need to brake for most of the corners.
You can bag this cheevo by simply setting up a custom race on California,Pacific Way. Really easy course so there's no need to brake just a lift of the throttle now and again will get you to the end in first place and even on the hardest difficulty the opposition rarly bothers you when you've got yourself in front of them....easy 30G's