The 20-year-old Kenyan, who ended the track season as world record holder at 3,000m and two miles, and overall grand prix champion, appeared to have the measure of a top quality field as he produced a series of early surges.
But Brown, who became the first British man to take a major cross country title in 21 years when he won the European Championships two weeks ago, kept his nerve and his steady pace to dispute the lead with the Kenyan and the South African runner, Hendrick Ramaala, in the final 2,000m of a hilly 9.3km course that was softer than predicted.
As the bell rang for the final 1,100 metres, Brown was only 10 metres behind the Kenyan, whose rhythm was broken every time he encountered an incline. The Briton took advantage of a long downward incline to overtake the Kenyan for the final time, generating enough speed on his run-in to hold off Komen's final sprint, finishing three seconds clear in 28min 24sec.
"I never knew what he would do next," Brown said of Komen. "But I was feeling really good over the last couple of laps. I don't get the chance very often to compete in Britain, so it was important for me to do well.
"There are a lot of runners in this country with as much ability as me. The difference is I don't think they prepare as well. I hope I have given them a target to aim for."
It was Brown's second major victory over a top Kenyan in the space of three weeks. As part of his European Championship warm-up, he had beaten the reigning world cross country champion, Paul Tergat, in a race in Spain.
Brown, now 25, is frequently referred to as a Yorkshireman, but he has led a peripatetic existence, having been born in Wales, and having studied at Iowa State University and based himself in Germany.
After qualifying for the Olympic 10,000m this summer - where he eventually finished 10th in the final - he castigated the attitude of many of his fellow British middle-distance runners, accusing them of a lack of genuine ambition.
His recent performances, and his 12th placing in the world cross country championships in March, the highest by a European, indicate his commitment to taking on the challenge of the Africans who currently dominate distance running.
Although this result can only increase his confidence, Brown declined to upgrade his target of a top-six placing in the next world cross country championships in Turin three months hence, saying: "There are guys out there who are nowhere near their maximum [today]. It will be a different ball game."
The women's race was won by Ethiopia's world cross country champion Gete Wami, who outsprinted Elena Fidatof of Romania and Britain's defending champion Paula Radcliffe after all three had moved clear of the rest of the field.
It was a satisfactory return to top class action for Radcliffe, who had not competed since October because of a knee injury. As ever, she produced a fully comitted performance, but faltered in the final 200 metres.Reuse content