Mo Farah collects his fourth London 10,000 win (Getty Images) © Copyright
Farah broke the British 10km road record in this event two years ago, but this time he left it late, content to bide his time in a leading group of five before pulling away over the last 200 metres to cross the line in 29:21, just three seconds ahead of Japan's Arata Fujiwara.
"My aim was always just to win rather than worry about the time or anything," said Farah, who finished more than a minute and a half outside his course record despite an imperious 2:35 last kilometer that left his rivals fighting for second place.
"I wanted to keep my winning streak going on this course. Racing is what I train for so it's great to come here and win again."
Farah's victory was never in much doubt despite the presence of Fujiwara and Kenato Nakamoto, the Japanese pair running as guests to get a feel for the Olympic marathon course where they will compete in 11 weeks' time.
Fujiwara briefly threatened to break clear at half way and finished strongly in 29:24, but it was Britain's Olympic Marathon hope Scott Overall who clinched third as only 18 seconds separated the top five.
In contrast to Farah, Yamauchi set off from the start of the women's race with a time target very much in mind. Aiming to finish in under 32 minutes, the Marathon star was disappointed to clock 32:52 as temperatures rose to the high 20s.
"The time was OK, but I was hoping to run a bit faster. I didn't feel that fresh," said Yamauchi, who was sixth in the Great Manchester Run a week ago.
"It was really hot out there on my own. And it was a tough course, with all those corners, and ups and downs."
"It was good to run on the Olympic course, though, and it's great to get a win on the streets of London with the Olympics just two months away. This tells me I'd like to be a bit further on in my preparations but I've just got to train hard. I‚m confident I can be in good shape."
There was no sign of disappointment for the woman in second place, however, as Caryl Mair Jones knocked more than half a second from her previous best to finish in 33:07 ahead of two of Japan's Olympic marathon runners, Yoshimi Ozaki and Risa Shigetomo, with Scottish favourite Freya Murray relegated to fifth.
"I really didn't expect that at all," said the Welsh runner. "That's definitely the biggest result of my career."
"I was focused on Freya for the first three kilometers but then I felt good so I started chasing Mara. I knew I couldn't catch her but I thought if I hang on to second place behind Mara Yamauchi that can't be bad."
If Jones produced the shock in the women's race, the only surprise in the men's was the rather pedestrian pace in the early stages.
Farah was happily tucked in behind the leaders as a large group clicked off kilometres of 3:04, 3:13, 2:48 and 3:05 to pass 4km in 12:10 when Fujiwara made the first significant move as they rounded the twisting corners of Leadenhall Market in the heart of the City.
Farah and Overall immediately covered the move and six emerged clear of the rest as they passed half way in 15:10. Six became five by 8km as the splits moved into sub-3 minute territory. Farah showed at the front for the first time along the Embankment and he led the field past the Houses of Parliament with Overall alongside and Fujiwara close on his heels.
These three struck for home along Horse Guards Parade but Farah was always going to be too quick, and the world 5000m champion showed his rivals a clean pair of heels as he turned into The Mall with a finishing kick as hot as the weather.
"It was a bit of a battle but I was comfortable and just needed to cover any moves," he said. "I am a track runner so I knew I could win it in a sprint."
Overall enjoyed his early season tester over the Olympic Marathon course as he finished in 29:26.
"It was a bit of a blow-out at the end," he said. "I felt strong but I'm not that fast yet and it showed over that last kilometer. The pace was pretty steady early on. The first 5km was slower than Marathon pace as we were all looking at Mo to see when he'd make a move."
"I felt comfortable till the last 800 metres, but this is the start of my marathon build-up and it was good to run on the course. I'm sure it'll help come August."
While Overall and Yamauchi now return to Marathon training, Farah heads back to his base in Oregon where he races over 5000m on the track next weekend against many of the top Kenyans and Ethiopians.
Asked whether this was a message to his Olympic rivals, Farah was characteristically cautious: "This shows that training is going well. But the win was more important than anything. It's just a good race, and it was nice to win on the Olympic course."
That was a sentiment echoed by more than eight thousand other finishers who sweated over the line behind him running fro UK Championship points, personal bests and charitable causes.
Matthew Brown for the IAAF
1. Mo Farah 29:21
2. Arata Fujiwara 29:24
3. Scott Overall 29:26
4. Mehretab Soloman 29:37
5. Kentaro Nakamoto 29:39
1. Mara Yamauchi 32:52
2. Caryl Mair Jones 33:07
3. Yoshimi Ozaki 33:17
4. Risa Shigetomo 33:20
5. Freya Murray 33:25