I think it took a while to figure all that out though.
Clearly the "hit and run" / "boom and zoom" tactic was not as simple or cut and dry as is often implied when you read about it. Planes like P-40, Spitfire, Hurricane, Wildcat, were maneuverable enough that they could turn with some Japanese planes, to a point. They just had to play to their own strengths. It took time to determine what the limitations of the enemy planes were. Very experienced pilots like DeHaven could bend the rules a bit more, just making sure to keep speed up.
Interestingly, both the A6M and the Bf 109 had similar traits of locking up in roll a bit at high speeds. They ended up only being able to roll in one direction above a certain speed.
So there was a standard escape maneuver (or a series of them) used by P-40 pilots both in the med and the Pacific / CBI, and I think pretty similarly, by Wildcat, P-47, P-51, Corsair, Spitfire and maybe Hurricane pilots too, namely to do an outside roll or split S into a steep dive, then roll opposite direction to the enemy fighter's torque (I forget if that was right or left for Bf 109 and A6M) and then skid or pull just a little bit of elevator, roll some more, skid or pull a bit more (this is to throw off shooting when the enemy fighter might still be pretty close), and then pull out at high speed, on a different trajectory. Then extend and come back at them.
This could be risky though because the Ki-43 and the MC 202 did not have quite the same problem with torque at high speed. The Germans also flew finger-four and had good radios, so you were never only worrying about the plane you see, there was always a good chance of another (or three more) that was coming for you too, and often at very high closing speed.
By the time they figured out overboosting though, below 10,000' the P-40s could definitely pour on the coal, and that helped a lot with both escape maneuver and followup / counter attacks.
Incidentally DeHaven's victory claims are mostly confirmed by Axis records. His second to last victory on Jan 23, 1944 for example was against a Ki-43 flown by Captain Shigeo Nongo, 15 victory ace, XO of 59th Sentai and commander of the 2nd Chutai, who was killed in action. His loss was a major blow to morale, as he was a popular leader, and it is recorded in the Osprey Ki-43 Aces book I've been summarizing in the Ki-43 thread.