|Saul Alvarez v Amir Khan (WBC middleweight title)|
|Venue: T-Mobile Arena, Las Vegas Date: 7 May (approx 04:00 BST on 8 May)|
|Coverage: Live radio and text commentary on BBC Radio 5 live and the BBC Sport website|
Amir Khan's trainer, Virgil Hunter, admits his charge lacks "killer instinct" ahead of his fight against Saul Alvarez in Las Vegas on Saturday.
Britain's Khan, 29, is moving up two weights to challenge his Mexican rival for the WBC middleweight title at the T-Mobile Arena.
If Khan won, he would be only the third ex-light-welterweight world champion to win a middleweight world title.
"Killer instinct has to be in you, you can't call it up," said Hunter.
"You see some kids in the gym and they want to hurt somebody. That's killer instinct.
"If they get beaten up they're back the next day, with a vengeance. That's a trait."
American Hunter was appointed Khan's trainer in 2012, following the fighter's knockout defeat by Danny Garcia.
|More about Amir Khan|
|When 12-year-old Khan met Ricky Hatton|
|Khan - why he can't win over doubters|
|Rise of Khan - iPlayer|
|'Khan v Mayweather unlikely to happen'|
|De la Hoya: Khan a superstar if he beats Alvarez|
|BBC 5 live boxing special - Khan preview|
Since that night, Khan has won all five of his fights but is a big underdog against Alvarez, whose only defeat in 48 pro contests was by American legend Floyd Mayweather in 2013.
On Wednesday, Khan conceded he did not have the power to hurt Alvarez and would have to rely on his speed instead.
However, Hunter claimed Khan's body punching was as good as anyone's.
"His left hook to the liver matches anything," said Hunter, who also trains Andre Ward, who is arguably the best pound-for-pound boxer in the world.
"The punch he put Marcos Maidana down with was as good as anything I've seen. He can really hit to the body.
"But I don't advise him to trade punches with Alvarez, because he's giving up too much size."
While the fight has been made at a catch-weight of 155lb - five pounds under the middleweight limit - Alvarez is expected to weigh almost a stone heavier on fight night.
Meanwhile, American boxing great Bernard Hopkins has compared Khan to Welshman Joe Calzaghe, who beat Hopkins in Vegas in 2008.
"Canelo is definitely the most powerful of the two," said Hopkins, a former middle and light-heavyweight world champion.
"But Khan's volume of punches reminds me of Joe Calzaghe. He's a guy who swarms you with punches so that by the time you get your bearings, the fight's over.
"You're not going to die, you didn't get hurt, but you've got so many bee stings you don't know where to scratch. You just know you've got to get the hell out of there.
"But Canelo wins on Saturday by knockout, in the ninth or 10th round."