I'm going to hit back with Freddie's help, says Khan

But if Roach's absence from the at ExCeL Arena is a cause of concern, the boxer believes the knowledge and confidence already imparted by his new trainer will be enough to see him clear the biggest hurdle of his career.

Roach was hired in the aftermath of Khan's shock 54-second defeat by Colombian Breidis Prescott in Manchester three months ago.

Although he suffers from Parkinson's Disease, the credentials of the American are immaculate. Roach has been voted trainer of the year in the United States three times and he boasts a roll call of past fighting talent that includes Oscar De La Hoya, Mike Tyson, Bernard Hopkins, Steve Collins and Wayne McCullough.

For his part, Roach was so impressed with Khan's potential, despite the manner of that setback against Prescott, to install him as No2 among the 14 fighters he trains in Los Angeles.

Unfortunately for Khan, Roach's priority remains Manny Pacquiao, the 29-year-old southpaw from the Philippines who is on Ricky Hatton's radar.

Some hours after Khan goes in against Oklahoma-based Dubliner Oisin Fagan in London, Pacquiao is due to take on De La Hoya in what is potentially the bout of the year in Las Vegas. And that is where Roach can be found.

Khan's corner will be manned by two of Roach's top lieutenants, coach Jesse Arevalo and conditioner Alex Arizo, in addition to Londoner Dean Powell. But the groundwork for a must-win fight has already been done in California.

"I'll be coming with new skills," said Khan, who is not the first British boxer to discover the benefits of training and sparring in an American gym. "Over there your sparring partners are hungry and they're out to beat you up but that's what you need," he said.

Khan has had good sparring sessions with Pacquiao and Roach has been impressed with what he has seen.

He said: "Amir has held his own - he's very talented. He's been beating the heck out of some of my other good guys. One of them got dropped and I don't know if he's coming back.

"Amir hits pretty hard. He's the only guy Manny doesn't play with because he can't afford to. They go at it. Amir gets the best of Manny early and Manny gets the best of Amir late."

That is hardly surprising. World lightweight champion Pacquiao is vastly more experienced, having had 47 fights and lost only three of them.

Khan, bidding for his 19th win in 20 contests, is up against Fagan, a 34-year-old who may have lost five of 27 but who has been stopped just once.

Defeat for Khan would deal a disastrous blow to his dream of emulating Pacquiao as holder of a world lightweight title but he insisted there will be no repeat of the Prescott shocker.

He said: "I made a big mistake by rushing in so I won't be looking for him. I'll be patient."

Perversely, Roach revealed the gameplan against De La Hoya is for Pacquiao to "attack, attack, attack".

His logic cannot be questioned. On paper, it is a mismatch. The fight has been made at welterweight (147lbs) but come the opening bell, some 24 hours after stepping off the scales, De La Hoya is likely to have bulked up closer to 160lbs.

Pacquiao started out as a light-flyweight but Khan said: "Manny's in great shape, very explosive and very fast and you don't know where his punches are coming from. He'll be too explosive for Oscar."