Rose stopped the Canadian in the 12th round on Saturday night after a hard-fought battle.
The 28-year-old, in the biggest fight of his career, revealed that the step up was not easy.
"I probably showed him too much respect," Rose told Sky Sports News.
"There was lots of pressure on me. It was a big step up, I've never felt that pressure before but I got him out in the end which I'm happy about.
"I felt him wobble [at the end] and kept the pressure on. I could've done it earlier. I was conserving some energy and shouldn't be doing that. I left it late."
Rose may have to vacate the British title that he won outright last year if he wants to move to European and world level.