How great was Conn? Let's keep it short. He turned pro at 18. He was 6'1 or so and had a 72 inch reach. That's about the same as Lucian Bute. He actually fought his early fights as a lightweight but pretty quickly grew into a welter. Conn learned as a pro and was 11-7 in his first eighteen fights in his first 14 months as a pro. But man oh man did he learn! Over the next 24 months Conn went 24-0-1 and grew into a middleweight.
Once he arrived at middle he knocked off HOFer Teddy Yarosz twice, HOFer Young Corbett III, #2 Solly Krieger twice, #6 ranked Babe Risko, #7 Oscar Rankins and reigning champ and HOFer Fred Apistoli twice in over the weight fights. Then Conn grew into a light heavy.
At light heavy Conn won the undisputed light heavy crown in a matchup with #2 ranked Melio Bettina after John Henry Lewis retired. Conn beat Bettina again in a rematch, defeated #1 ranked future champ Gus Lesnevich twice and then decided to try the heavies.
At heavy Conn beat #2 Bob Pastor, #8 Lee Savold and then he got his shot with Joe Louis. After that loss he beat HOFer and reigning middle king Tony Zale.
The WWII intervened and Conn serves for four years and is done. He has done all this by the time he is 23!
So let's spend 15 seconds with Billy Conn. This is round 12 of the first fight with Joe Louis. Conn is giving up four inches in reach and 35 pounds in the ring. The core of his strategy to this point has been circling to his left rapidly enough that Louis had to reset over and over again.
Pick it up at 3:37
3:37-Conn is in tight, a position he has sought to obtain occasionally up until now (and he has been forcing rotation even in tight). Conn's chin is tucked, his weight ir on his front foot so Louis can't push him around and his right hand has pinned Louis' left to his chest so he can't punch with it.
3:38-Even giving away 35 pounds Conn forces Louis to take two steps back and as Louis moves Conn lands a swift left and then a right to Louis' body.
3:39-Louis responds with a pair of hooks of his own, but because Conn is in tight and Louis is being pushed backwards Conn is able to smother them.
3:40-Conn lands a rabbit punch while Louis steps to his hight and troes to spin Conn.
3:41-3:45-Louis is now able to use his weight to walk Conn back to the ropes.
3:46-A now squared up Conn takes a left to the belly.
3:47-Louis follows up with a short right and left downstairs. Conn steps back slightly with his right foot and forward with his left so he is once again in a power position and in position to punch.
3:48-3:49-Conn is now able to walk Louis back to the center of the ring because Louis is squared up and Conn isn't. Conn's head is on Louis' left shoulder.
3:50-Conn removes his head from Louis' shoulder, centers it up, shifts his weight onto his left foot and attacks! The first punch is a left hook to the body which Louis largely blocks with his right elbow. At this point Louis makes a rare error. He lifts his right foot first when moving left and Conn makes him pay.
3:51-While all Louis' weight is on his left foot, Conn follows the hook to the body with a drop step with his right foot that has the effect of rotating his body clockwise so he re-optimizes punching position. Immediately a left hook upstairs, then steps with his left foot and rotates his hips and shoulders back to the left and crashes home a short inside right hook. Kind of an odd punch, but a perfect one given this situation. This punch is so hard it lifts Louis' left foot entirely off the canvas.
3:52-Conn finishes the four punch combination with another left hook upstairs that staggers Louis. The two men have rotated 90 degrees in the last two seconds.
This is as close as Billy Conn ever gets to the heavyweight crown. These fifteen seconds demonstrates how exceptional craft, courage, desire and a speed advantage can, for at least brief periods, overcome disadvantages in height, reach and weight.