We recently had one of our "youth sailors" leading in a long race, upwind and down wind twice. When the second boat was able to sail "low and fast" enough to get some "separation" so when he sailed into the last header he tacked, crossed the "youth" and won the race--- he was only ahead at the finish.
If you are ahead don't let them have the separation. Stay pretty well up wind and if the second boat is sailing low and fast on a lift, then go low and fast with him. OK, if you think this a header and for some other reason you want to stick with it, then high and slow maybe be OK.
If you have the fleet right behind you, then sail the course, but don't forget to sail low and fast toward the next header.
Check out the "Lasers Climb the Ladder" in November.