The judges scored it 30-27, 30-27 and 30-26 for the young Swede, although it wasn't quite as one-sided as the scores indicated.
Gustafsson certainly was the superior fighter on the night though. He floored Shogun in the early moments of the fight and never really let up, fighting a controlled fight throughout. His best punch was the uppercut, which he landed multiple times throughout the three-round affair, but he also showed good variety in his attack, scoring six takedowns, employing knees and at one point in the third, wobbling Rua with a front kick.
Rua, as always, showed an incredible chin and an unbending will, refusing to give in during any of the barrages that came his way.
Gustafsson too showed an excellent ability to absorb damage, as he fended off all of Rua's comeback attacks.
According to FightMetric, Gustafsson out-landed Rua 128-51 in the bout, notably turning it on in the third with a 53-11 advantage.
The win could set up Gustafsson with a title match against the winner of April's Jon Jones vs. Chael Sonnen bout. However, others like Glover Teixeira and Dan Henderson can also make a case for the slot.
Gustafsson has won six fights in a row, moving to 15-1 all-time.
Rua has alternated wins and losses in his last eight fights, dropping to 21-7.