Amir Khan believes he will face the sternest test of his career when he goes head to head with Zab Judah in Las Vegas on Saturday night.
The 24-year-old is looking to add Judah's IBF light-welterweight title to his own WBA belt at the Mandalay Bay Hotel and is under no illusions about the task in hand.
A top-level campaigner for more than a decade, Judah first picked up the title he currently holds when he climbed off the canvas to stop South Africa's Jan Piet Bergman in 2000.
Meetings with the likes of Floyd Mayweather, Kosta Tszyu and Miguel Cotto followed for the 33-year-old American southpaw who has operated with distinction across two weight classes.
"I think he could be the toughest one yet," said Khan. "He's a five-time world champion and a two-weight world champion.
"He's very experienced. He's got skill and that southpaw style which is very awkward."
Nevertheless, Judah has tasted defeat six times during a 49-fight career and Khan is confident of a victory he thinks could send his opponent into retirement.
"There is always a young lion coming up and I'm going to take him out and take his throne," said the Bolton fighter. "I want world titles and he holds a world title.
"It's a unification fight and I hope he's been training hard because once I win I think that's it for Zab Judah, I think he'll have to hang his gloves up."
Many good judges expect the clash between two slick operators to produce its share of fireworks, something Khan welcomes after his previous outing against against another southpaw, Northern Ireland's Paul McCloskey, came to an unsatisfactory conclusion.
Khan had been awarded every round by all three ringside judges when an accidental clash of heads in the sixth round opened a cut above the left eye of European champion McCloskey and brought an early conclusion to a scrappy bout.
Controversy ensued as the Irishman's camp insisted their man should have been allowed to continue with an injury that required seven stitches.
Although Khan largely agrees with this stance, he feels McCloskey was complicit in his own downfall.
"I'd have finished that fight quite differently if it was up to me," he said. "If I was the referee I'd have let the fight continue.
"But even if I was Paul McCloskey I would have tried to force the ref to let the fight continue.
"It seemed to me when the ref was having a look at him and calling the doctor in that Paul McCloskey was just quiet. If that was me I'd have been saying 'I'm fine, I'm fine'."
Khan is keen to move on from that April clash at Manchester's MEN Arena, but feels it served its purpose in preparing him for the upcoming showdown with the light-welterweight division's most decorated left-hander.
"I think that fight was good because it gave me experience against a southpaw and I hadn't fought one for a long time," he added. "But now I've got that little bit of experience going into the Zab Judah fight.
"I've been using a lot of the tactics that I used against McCloskey in training and we're going into the fight using a bit of that and elaborating on it a little bit more."