Reigning WBO world light-heavyweight champion Nathan Cleverly has, along with England's George Groves, been sparring with Mikkel Kessler in his preparations ahead of the rematch with Carl Froch on Saturday night.
He has seen at first hand the mental and physical condition of the Copenhagen-based boxer, 33, who has indicated he could retire should he lose to Froch on Saturday, and feels the eagerly-anticipated showdown is too tight to call.
Cleverly said: "It's going to be a good fight, they're both evenly matched.
"They had a war in the first fight and it's going to be a pretty similar second fight.
"It's 50/50, really. It's too hard to call this one but I think that's what makes it so interesting.
"Kessler's looking sharp, looking good, some nice movement and he's up for it. He knows he's got to win this otherwise he could be looking at retirement, he's going to give it everything, for sure."
