Graham said he was "devastated" by the defeat but would not be advising him to retire, as it was not his decision to make.
"I won't decide, he will - he's in his physical prime," he said.
"If I thought he was slipping, I'd be the first to advise him to retire, but the way I feel is if he wants to carry on, I'll be with him until I do see those signs.
"If he wants to retire I've got no problem with that, but he's at his peak so how can you ask a man to retire?
"He doesn't really need to fight any more but it's entirely up to him. I'll be with him as long as he needs me - I love training him."