Well the P-47 could be superior on the Mustang

P-47 Reigns Supreme over P-51 Mustang
Don Whinnem B-17 Escort Mission
352nd FG ETO -
We were escorting B-17s. I was flying Al Marshall's wing. We got into a mixup and got separated from the Group. I looked over my left shoulder and saw something coming in. I called , 'Al, there's a bandit coming in at 7 o'clock high'.
We did a scissors. Al broke left, I broke right and when I completed my circle it looked like Al was being shot up by an ME109 I put the throttle to the firewall, poured on the water injection and got on his tail. When I got within 200 yards I started firing and got strikes all over the plane. But as soon as he was hit he broke up sharply, and only then did I see the square wingtips and square tail. It was a P-51!
I called our Group Commander, Col. Joe Mason, a real tiger, and said 'Sir,there are some P-51s in the area'. He came back, real caustic, 'The hell they are. They're 109s. Shoot the bastards down'. 'But sir, one of them is a P-51 and I just shot it up pretty good'. Silence.
Well, I located the P-51 again, and by this time he knew we were 47s, so I pulled up alongside to take a look. I didn't know it was Glenn Eagleston, but he looked like he was hurting. There was nothing I could do, so I left him and joined our formation.
I got part of the story later that day and the rest of it 3 months later. It went all the way up to the 8th Fighter Command Hqs......A p-47 had shot up a P-51. Col Mason had to go up there and explain it to the brass. But our story held up. The P-51 was 150 miles off copurse, and his camera film showed him shooting at a P-47.
The trouble was that an FW190 and a P-47 have the same silhouette. You have to see the planview to see the elliptical wings.
Three months later I crash landed near a 9th AF base, and was taken to their hospital with a banged up nose and forehead. Eagleton was stationed there and they knew my name from the flap at Hqs, so he looked me up and we drank beer at the club and flew the mission all over again.
Eagleton swore he was shooting at a FW190, and even my camera film looked like I was shooting at a 109 to our Intelligence Officer. Glenn said the only thing that saved him was the armor shield behind the cockpit.. The bullets came in over his shoulder, hit the instrument panel, knocking most of them out.. When he got to his base it was weathered in and he was forced to bail out. His instruments were too shot up to try it.
And that's how Don Whinnem shot down Glenn Eagleston - something no German pilot was able to do. Glenn ended up with 20 1/2 confirmed victories, tops in the 9th AF. Whinnem was no slouch either. He didn't get credit for that P-51, but he got enough 109s and 190s to make him an Ace.