I always hate these who's better, Jango or Boba Fett, since I love both Mandalorians. But to put it simply, in the "Attack of the Clones" novel when good old papa Jango is training his cute lil sociopathic cloned son Boba. He notes mentally to himself that Boba is better at a pistol or somesuch than he was at Boba's age. Which of course is how Jango wants it, he wants his kid to be the best.
Course at ten Jango was working on a farm with his dad when the Deathwatch and the True Mandalorians came into his life. Boba at ten was training with his Mandalorian bounty hunter dad when a noisey Jedi knight, one Obi Wan Kenobi, came into the picture. Who knows what would have happened if Boba got picked up by one of the Mandalorian instrutors after geonosis,maybe he would have turned out exactly like his old man?
As for a combat situation, never would happen. Jango loved his rotten kid way too much,and Boba idolized that old fart like nobody's business. They would rather stand back to back and go down fighting the entire universe than go against each other.
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf."-George Orwell