I agree with Ded. Lengro and I did Yak vs P51 a couple of days ago. The P51 was the boss of that fight no doubt, the only chance the Yak had was in creating an E advantage
Films or it didn't happen

I guess this is my point about how there are so many variables including the pilots personality that will influence the results. I did not assume a controlled environment when I wrote my post but even in there, I would be dead or have killed the yak before any thoughts about going vertical would come into play.
As always in Plane vs Plane thread we go to Pilot vs Pilot thing.

Story:
Before last scenario I had DA training Spit9 vs 109G6 with top 109 stick. First 6 fights i got owed. Then I started to wining. After 10th I was seal clubbing him.
I found out how counter his merges and tricks. Then I switched to 109 and I was owed again no matter how long I tried.
I knew what he is going to do but couldn't make it better and this time my plane was not making up for my worse flying.
My point is:
In 500 co E fights ( no matter cage or bracket rules ) Dedalos in P-51D vs Dedalos in Yak9U last 100 fights and every next one Yak is the winner.
It's hard to find maneuver that Yak can't do better in twins duel.