Trainer Adam Booth has insisted that British super-middleweight James DeGale needed to make improvements in order to have a chance of winning a world title.
Booth was in George Groves's corner when DeGale suffered his only professional loss in 2011, but he believes that the Londoner has made a number of adjustments ahead of his IBF title clash with Andre Dirrell in Boston on Saturday night.
Booth told Sky Sports News: "James's improvements have come over a short space of time because for the majority of his career, from what I saw, he was lacking certain things.
"He couldn't break out of his set mould, but he has done that over his last couple of fights."
Booth, who also used to train former heavyweight world champion David Haye, recently helped Irishman Andy Lee win the WBO middleweight title.