American record holder Deena Kastor believes Paula Radcliffe will be in shape to put on a "spectacular performance" in next Sunday's Olympic marathon.

Radcliffe's rivals are rapidly becoming her biggest fans, and Kastor is among the world record holder's most fervent admirers.

She recognises that "anything is possible in a marathon", but added of Radcliffe: "It is obvious she is the woman to beat."

With just a week of preparation left until the marathon takes over the streets of Athens on August 22, the anticipation of Radcliffe's performance is building.

It should be one of the Games' highlights, and Kastor said: "She's the world record holder in the event and any time she gets out there she's well prepared and puts on a spectacular performance."

Radcliffe will have no assistance from pacemakers in the race, but she is a masterful frontrunner, as exemplified by her two marathon victories in London, and one in Chicago.

By keeping her races to a minimum, Radcliffe has been able to tailor her training to specific events, and she is currently training in Spain.

The heat there should ready Radcliffe for Athens, where temperatures have soared into the high 30s in recent days.

If Radcliffe gets her race plan right, there should be no stopping her, even if the world record of two hours, 15 minutes and 25 seconds may be out of reach.

"I don't think she's vulnerable at all," emphasised Kastor.

"There's no doubt about it. She comes out in shining colours most of the time."

Radcliffe has made only two track appearances this summer, both of which showed her to be in fine shape.

She shattered the European 5,000metres record in mid-June and then ran the fastest 10,000m in the world this year a fortnight later.

However Radcliffe's longest race since victory in last year's London Marathon was run when claiming the IAAF world half-marathon title last October.

Radcliffe's reluctance to compete regularly on the marathon circuit should not be a hindrance to her claiming gold, according to Kastor, who is ranked fourth in the world this year over the 26 miles and 385 yards distance.

"I think she's always done an awesome job preparing herself for events," said the American.

"So she'll be ready on the evening of the 22nd."

If there is to be any concern lurking in Radcliffe's mind, then it might be that many consider her champion-in-waiting, and some athletes will be out to prove that marathon running is about more than just one woman.

"She's very well respected which she deserves," said Kastor, "but she'll be the woman that everyone is hunting down.

"She's definitely the hands-down favourite in this event but that's not to say there are four or five other women who could also bring home the medal as well."

Potential rivals to Radcliffe would have to include the Kenyan pair of Catherine Ndereba and Margaret Okayo, but Kastor reckons is confident that she too could be a medal contender.

"I have the fourth fastest time coming into the marathon, so if I can just slide past one more girl up there during the race, I'll be there," said Kastor.

"I feel I have prepared just as possibly as best as I could. But there will be 60 other girls out there who will feel they have prepared just as well.

"To me I just think everybody is beatable, especially in a marathon where anything can happen.

"I was this hands-down favourite in the Olympic trials in the United States - then I found myself marching backwards to a second place.

"It's the race that brought me back to being hungry in the sport again, to make sure I do things right going into this marathon."