Britain's Paula Radcliffe had to settle for second place in the Great North Run as Kara Goucher eased to victory.
Goucher strode away from Radcliffe to ease to victory in Newcastle
Radcliffe, competing in her first race for 21 months, began at a good pace and kept up with Goucher for the first six miles but the American then broke free.
By the 10-mile mark, Radcliffe was looking ragged and left trailing.
Goucher finished 56 seconds clear in one hour, six minutes and 57 seconds to set the year's fastest half-marathon and the eighth quickest in history.
But the main story was Radcliffe's first competitive outing since giving birth to daughter Isla in January and a related back injury.
The racing instinct and mentality comes back straight away but it takes the body time to catch up
And she was given a clear indication, which she wanted, of where she is in her preparations for next year's Beijing Olympics.
"It's a good place to start and where I really want to run fast is Beijing," Radcliffe told BBC Sport.
"The racing instinct and mentality comes back straight away but it takes the body time to catch up, especially because I've been training at altitude.
"I don't want to be flying now because it's a long time to hold on but at the same time I want to be winning races.
"My pride's taken a little bit of a bashing. I came out here wanting to win the race but it is good to be back."
The 33-year-old marathon world record holder started confidently enough but eventually had no answer to Goucher, who produced an astounding performance for a woman who had never previously run such a distance competitively.
Running alongside her the first few miles I just thought: 'Hopefully someone is getting a picture of this'
Goucher, who won bronze in the 10,000m at the World Championships last month, said: "My focus all year has been Osaka and it wasn't until after that that this was even an option.
"I'd never run anything longer than 10k so I just wanted to stick with the leaders for as long as possible.
"It was pretty funny, people thought I was Paula the whole way. I felt so bad that I was crushing everybody!
"Running alongside her the first few miles I just thought: 'Hopefully someone is getting a picture of this'."
London Marathon winner Martin Lel burst clear of fellow Kenyan and world half-marathon record holder Sammy Wanjiru to win the men's race by eight seconds.
The duo made the early running along with three-time winner Hendrick Ramala of South Africa but pulled clear by the halfway mark.
Their times for each mile varied wildly, and the pace dipped considerably by the 10-mile mark, but their battle was intense until the end, when Lel powered home.
In the wheelchair races, South African Ernst Van Dyk (42:36) beat Kurt Fearnley of Canada, while Britain's Shelly Woods (50:36) cruised to victory ahead of Italian Francesca Porcellato in the women's event.
England football manager Steve McClaren and former Eastenders star Charlie Brooks were among the celebrities who joined almost 50,000 in competing in the world's biggest half-marathon.
The race was started by another ex-England boss, Sir Bobby Robson.
1 M Lel (Ken) 1hrs 00mins 10secs
2 S Wanjiru (Ken) 1:00:18
3 H Ramaala (SA) 1:02:37
4 T Abyu (GB) 1:02:50
5 J Rohatinsky (USA) 1:02:54
6 A Goucher (USA) 1:03:17
7 R Ribos (Por) 1:03:36
8 D Berhanu (Eth) 1:03:54
9 W Chinhanhu (Zim) 1:03:56
10 I Hudspith (GB) 1:03:59
1 K Goucher (USA) 1hrs 06mins 57secs
2 P Radcliffe (GB) 1:07:53
3 A Kalovics (Hun) 1:10:17
4 J Muia (Kenya) 1:11:49
5 H Yelling (GB) 1:12:14
6 S Partridge (GB) 1:12:33
7 T Morris (GB) 1:13:22
8 A Zekiros (Eth) 1:14:08
9 B Dagne (GB) 1:14:11
10 T Mezentseva (Ukr) 1:14:17
Men's wheelchair result:
1 E Van Dyk (SA) 42mins 36secs
2 K Fearnley (Aus) 42:37
3 J Cassidy (Can) 43:44
4 D Lemeunier (Fra) 44:37
5 R Brunner(Spa) 44:51
6 T Patel (GB) 47:09
Women's wheelchair result:
1 S Woods (GB) 50mins 36secs
2 F Pocatello (Ita) 58:00
3 J Sowerby (GB) 58:40