Adonis Stevenson stopped challenger Andrzej Fonfara 28 seconds into the second round to retain his WBC world light heavyweight title on Saturday.
The 39-year-old made quick work of the rematch as Poland's Fonfara barely survived the opening round at the Bell Centre Arena in Montreal.
Fonfara's trainer Virgil Hunter stepped in and stopped the fight early in the second round because his boxer was taking too much punishment.
"I was very focused on him. I took my time and finished the job," said Stevenson.
"I caught him with my left. I knew he was coming so I took the punch."
The fight was a rematch of their action-packed meeting in 2014, when Fonfara sent Stevenson to the canvas but was knocked down twice himself as Stevenson won by scores of 115-110, 115-110 and 116-109.
On Saturday, Fonfara was the first to hit the canvas in the opening round. Stevenson hurt him with a hard left to the temple, which was followed quickly by the knockdown.
Later in the round, a helpless Fonfara had to be saved by the bell after Stevenson trapped him in the corner and was landing punches at will.
Stevenson now boasts a record of 29-1-KO24, and has previously talked about unifying the division, with a bout against the winner of Sergey Kovalev and Andre Ward potentially next in the making.