Undoubtedly, but he wasn't a genius commanding and organizing fleets in battle...
He is a sub specialist. He represents the Italian frogmen doctrine. Please note that Italian frogmen sunk, or severely damaged, about 100,000 tons of Allied warships and 131,527 tons of merchant shipping. Please find below a short list and a link to a webpage
NAME TONNAGE LOCATION DATE
Durham 10,900 Tons Gibraltar Sep, 1941
Baron Douglas 3,900 Tons Gibraltar July, 1942
Raven's Point 1,900 Tons Gibraltar July, 1942
Kaituna 10,000 Tons Mersin July, 1943
Meta 1,600 Tons Gibraltar July, 1942
Camerata 4,900 Tons Gibraltar May, 1943
Stanridge 6,000 Tons Gibraltar Aug, 1943
Queen Elizabeth 32,000 Tons Alexandria Dec, 1941
Valiant 31,000 Tons Alexandria Dec, 1941
Harmattan 4,600 Tons Algiers Dec, 1942
Jervis 1,700 Tons Alexandria Dec, 1941
Mahsud 7,500 Tons Gibraltar May, 1943
Fernplant 7,000 Tons Iskenderun Aug, 1943
Empire Centaur 7,000 Tons Algiers Dec, 1942
HMS York, 10,350 tons Suda March 1941
ref
http://www.comandosupremo.com/Decima.htm