Possible Clues:

• Successful person - Crufts' winner?
• The master or victor in canine analogy
• Capo to kill boxer, perhaps
• Thirteen, overall winner at Crufts
• First to follow leader
• To bring back trophy, follow one who's most successful
• Master or victor, by canine analogy
• Sirius, high in the sky?
• Champ
• Member of learned society