Bruce had natural assets such as strength, speed and endurance that would have aided him in any sport provided he dedicated himself to it. However Bruce's true strengths lie in his ability to adapt to any situation. If you are fighting a boxer - then take him out of his element to groundfighting or kick his legs out from under him. If you're fighting a jiujitsuan - then force him to fight you standing and keep him out of his element. If you're fighting a Mixed Martial Artist - then introduce him to street techniques such as getting kicked with a boot or choking them with a shirt collar. The variations are endless.
Unfortunately the only recorded fight that Bruce Lee had was amature boxing match against Gary Elms which Bruce won after knocking Gary down several times. After the fight Gary was quoted as saying Bruce punched like a mule. Bruce was later quoted as saying, the problem with ring fights is there's too many rules. A few years later Bruce was challenged in a sparring boxing match by pro boxer, Joey Orbillo , who later admitted trying to stop Bruce's punches was like trying to catch smoke. And was not able to land a single hit on Bruce. Both of those incidents can be found doing a little research ie Google. For the people who still doubt Bruce's abilities I suggest reading the book : Bruce Lee The Untold story. Which chronicles Bruce's early training and street fights with gang members.
Research is the key , Bruce's only recorded boxing match against Gary Elms which Bruce won after knocking Gary down several times. Years later Bruce would have a sparring match with pro Boxer Joey Orbillo Later Joey admitted in his book how he lost that sparring match against Bruce Lee, Joey was quoted as saying trying to stop Bruce's punches was like trying to grab smoke .and was not able to land a single punch on Bruce.. There is a book that chronicles Bruce's early training and street fights in Hong Kong with gang members. It's called : Bruce Lee the untold story ..
Bruce Lee even the name has come to mean "the best & hardest worker in marital arts". Even cartoons like Naruto must use such characters like Rock Lee to associate with hard work and skills developed from hard work. Why do you think the UFC main guy in the monopoly lawsuit is Cung Le UFC tried hard pulled all kinds of tricks to keep him, that name value was well used. And why do you think One Championships clings so hard to the Lee family bringing in the younger Lee siblings and selling them hard as prodigies?