This is not referring to your time ahead of the second place place finisher in your own group. This is referring to the overall times of all 4 groups. I recommend going all out and getting first place (out of all 4 groups) in the first qualifier. This will mean for the second qualifier you will be placed in Group D which goes last, which means you'll be able to see the times set by the winners of the other three groups in the next qualifier. Then when you get close to the end of the race, slow down if necessary so that you finish less than a second ahead of the next best time.
As always, you can set the AI difficulty to 1 (Very Easy) to make it easier to set the best time.