If he is gone after fist corner it probably means that you are braking too much in first corner. In video from MistahMCA you can see how he is doing it. Video shown down in this post.
( If you want to study video, go on settings (cog wheel) in YouTube and you can select playback speed, drop it down to 0,25 of speed and then in video watch lap time timer in the middle of the screen. Count time shown in miliseconds and at same time check when he is pressing brakes.)
We can see 100 meter board on right hand side and starting braking just after 100 meter board. So he is exactly at 03 seconds of the lap time when he hits the brakes to 100% and then after half a second he starts releasing brakes to reach 50% of braking power when lap time approximately reaches 4 seconds. That means hit full power for half a second, release gently during next half of a second to reach 50% of brake power. Then after first second of braking, slowly release from 50% of braking power to no brakes at all until you reach just before apex, and that takes just a bit more than half a second.
I assume you are turning in by 50 meter board and full acceleration as you hit apex, right.
Practice just first corner until you keep up with the ghost. If he is gone after T1, that means he was not braking so much as you did, so try to press brake a bit shorter time in next attempt, if he is still gone then shorter brake press in next attempt, until you are there at same distance to the ghost after first turn.
When you have mastered first turn, you can try same approach to T2 and so on to try to keep same distance to ghost before and after turn.
You got this champion!