Britain's Paula Radcliffe held off Gete Wami in a thrilling sprint finish to win her second New York Marathon.
Radcliffe twice tried and failed to shake off the Ethiopian as the race reached its climax, and her great rival briefly threatened to snatch victory.
But the 2004 winner put in a final burst to leave Wami behind and broke the tape in 2hrs 23 mins and 9 secs.
She told BBC Sport: "I've had years of her outsprinting me and I wasn't going to let it happen again."
Wami, 32, perhaps paid the price for successfully defending her Berlin Marathon title just five weeks before the Big Apple race.
Radcliffe, 33, who gave birth to her first child, Isla, in January, was competing in her first marathon since winning the world title in Helsinki in 2005.
"People thought having a baby would be the end of my career - I never thought it would be"
Running in dry, sunny conditions, she and Wami soon left the rest of the women's elite field trailing in their wake.
Radcliffe reached the halfway point in 1hr 10.40 secs, but that new course record pace slowed in the later stages.
She led for virtually the whole race, but admitted Wami gave her a scare when she drew level in the final mile.
"It was tough - I didn't have the breathing problems I usually get towards the end, but my legs felt very tired," she said.
"I just kept repeating to myself 'I love you Isla' to keep my rhythm going."
Radcliffe paid tribute to American elite runner Ryan Shay who collapsed and died during Saturday's US men's marathon trials in Central Park.
606: DEBATE
"This (winning) is sport but that is a tragedy, and it puts everything into perspective," she said.
Radcliffe has now won all seven of the marathons she has finished in her career - only at the 2004 Olympics in Athens did she drop out.
Her winning time on Sunday secured her Olympic berth for Beijing 2008.
Wami finished 23 seconds behind, with two-time defending champion Jelena Prokopcuka a distant third in 2:26.13.
Kenya's Martin Lel, who won the London Marathon in April, triumphed in the men's race.
As he did in London, he burnt off Morocco's Abderrahim Goumri in the last few hundred metres to win in 2.09.04.
South Africa's Hendrick Ramaala, who won in New York in 2004, finished third in 2:11.24.
Edith Hunkeler of Switzerland won the women's wheelchair race ahead of Britain's Shelly Woods.
Women's race results:
1. Paula Radcliffe (GB) 2 hrs 23 mins 09 secs
2. Gete Wami (Eth) 2:23:32
3. Jelena Prokopcuka (Lat) 2:26:13
4. Lidiya Grigoryeva (Rus) 2:28:37
5. Catherine Ndereba (Ken) 2:29:08
6. Elva Dryer (US) 2:35:15
7. Robyn Friedman (US) 2:39:19
8. Tegla Loroupe (Ken) 2:41:58
9. Melisa Christian (US) 2:42:07
10. Alvina Begay (US) 2:42:46
Men's race results:
1. Martin Lel (Ken) 2 hrs 09 mins 04 secs
2. Abderrahim Goumri (Mor) 2:09:16
3. Hendrick Ramaala (SA) 2:11:25
4. Stefano Baldini (Ita) 2:11:58
5. James Kwambai (Ken) 2:12:25
6. Ruggero Pertile (Ita) 2:13:01
7. Stephen Kiogora (Ken) 2:13:41
8. Marilson dos Santos (Bra) 2:13:47
9. Aleksandr Kuzin (Ukr) 2:14:01
10. William Kipsang (Ken) 2:15:32
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