Day 3, Goal 5:

"Our editor actually drives a 911 Turbo - we'd love to finish up with a high-speed chase around the Silverstone National course.
Stay within 100 yards (91m) of the opponent."

I did this twice without a problem, but didn't get a green banner ("succeeded") or a red banner ("failed"). It just let me do the goal again and again.

So I just went for winning this H2H and overtook him right in the first corner and didn't bother about staying behind him --->   green banner, goal accomplished.