Horn was able to celebrate one of boxing's great shock triumphs at Brisbane's Suncorp Stadium as the three judges scored Sunday's fight 117-111, 115-113 and 115-113 in his favour.
CompuBox statistics showed modern-day great Pacquiao, a huge favourite coming into the fight, was more than twice as efficient as his opponent when it came to the percentage of punches landed.
Horn also came close to being stopped in round nine, but Pacquiao nevertheless refused to condemn the decision.
