The 28 year-old cancer survivor engaged in an enthralling battle with the pre-fight underdog, but ultimately had too much in his locker and took the victory in the final round.
A points decision looked on the cards until Jacobs backed Truax onto the ropes and forced referee Dave Smith to intervene to seal a 26th career stoppage.
The champions is now 29-1 for his 30-fight career, whilst Truax drops to 25-2-2 but did no damage to his reputation whatsoever.
In the co-feature, Anthony Dirrell lost his WBC super middleweight belt and the chance to face George Groves in a lucrative summer mandatory clash.
Badou Jack, a Floyd Mayweather protege, took full advantage of his negotiated voluntary shot at the coveted green belt to claim a majority decision after twelve rounds.
The fight could easily have gone the other way, although nobody could argue as Jack was handed a 116-112, 115-113 triumph as a third judge carded a 114-114 draw.
Jack, 31, becomes Mayweather’s third world champion as a promoter following Ishe Smith and Mickey Bey in picking up a recognised strap.
