One thing that will help you in all fights....
You took your view off of the P-39 too often, way too often. Practice flying where you look, not look where you fly. In other words, keep the other guy in view as much as possible. Head out of the cockpit. Except to clear your six, always track the bad guy. Don't look back into the cockpit. It takes practice to get accustomed to not having any concrete visual reference while flying, but it will greatly improve your in-fight SA to do so.
You need only check for visual reference (or glance at the altimeter) when you are in close proximity to the ground. When beginning at higher altitude, keep the bad guy in view constantly whenever feasible.
My regards,
Widewing