Far more usual scenario...
In 51 with plenty of E, come into a potential HO situation with a Spitfire IX. Taking the HO is not a good idea, so take the low road under the Spit. If he tried for HO he is low nose, and maybe even silly enough to split-S. The 51 now noses up and goes for a big, slow, climbing turn. This places the 51 in the position to continue to bounce. The Spit will likely fall into the pattern of breaking hard for overshoot, possibly up or down. You can keep outturning him in the vertical plane for a bit. The break point (that is, the place where you get lost) is where you can no longer maintain a comfortable vertical advantage.
All this really means is you can use superior E to outturn the Spit, or any other plane. When your energy states grow more equal you need to extend.