She recaptured the thrill of racing at the same event Sunday, but with a new twist -- this time, when she won, she celebrated as a mother, holding her 9-month-old daughter Isla.
Radcliffe and Martin Lel each pulled away during the final mile to win a second NYC Marathon title on a cool, sunny day with 39,085 runners starting.
"I've really, really missed it," Radcliffe said. "It's way more fun than cross training in a pool or cross training in a gym, and that's what it's all about. That's what keeps me motivated to work hard and to cross train hard is just getting out there and enjoying the atmosphere."
Radcliffe, the world-record holder from Great Britain, made a triumphant return in her first marathon in more than two years. She outlasted Gete Wami of Ethiopia, who was running her second marathon in 35 days. She won in 2 hours, 23 minutes, 9 seconds, beating Wami by 23 seconds. Two-time defending champion Jelena Prokopcuka of Latvia was a distant third in 2:26:13.
Lel had a better finishing kick than Abderrahim Goumri of Morocco, as they reprised their showing in April's London Marathon, when the Kenyan edged Goumri by 3 seconds.
On this day, Lel's time of 2:09:04 bested Goumri by 12 seconds in the first NYC Marathon without a pacesetter. Hendrick Ramaala of South Africa was third in 2:11:25.
"What I was doing is, maybe during the last sprint, sometimes you can lose, sometimes you can gain," Lel said. "So I said, 'Let me try to see.' "
A day after elite distance runner Ryan Shay died during the U.S. men's marathon Olympic trials in Central Park, officials held a moment of silence for Shay before the start of the men's race.
For Radcliffe and Wami, running neck and neck is nothing new. While this was their first meeting in a marathon, they've had lots of duels on the track and in cross country over the years.
"I've been there so many times with Gete on my shoulder coming into the final 400 meters," Radcliffe said, "and I was determined that this was my turn, this is the marathon this time, and I think a little bit to my advantage the last 400 meters because it's uphill, not like a track race."
Wami briefly passing Radcliffe in the final mile. But when Radcliffe surged back past her, Wami couldn't catch up again.
It was still a victorious day for her. By beating Prokopcuka, she captured the inaugural World Marathon Majors title, worth $500,000.
Radcliffe won $170,000 for the victory, including a time bonus; Lel earned $160,000 with the bonus.
Seven-time Tour de France winner Lance Armstrong finished 698th in 2:46:43 in the men's division.