Rebellin's strategy proved perfect over the 195.5km course
Italian veteran Davide Rebellin secured his third Fleche Wallonne title with a powerful sprint on the final climb.
The 37-year-old charged away with 200m to go on the Mur de Huy climb to beat Luxembourg's Andy Schleck and third-placed Damiano Cunego of Italy.
"This was my nicest win of the three," said the Serramenti Diquigiovanni rider, who also won in 2004 and 2007.
Barloworld's Chris Froome was the first British rider to finish, coming in 43 seconds behind Rebellin in 34th place.
Rebellin joins Marcel Kint, Eddy Merckx and Moreno Argentin as a three-time winner of the 195.5km Belgian event.
With 4km remaining, the peloton reeled in a group of six riders and Nicki Sorensen launched an attack.
But the Dane was outgunned and Rebellin burst past Schleck and Australia's Cadel Evans to secure his triumph.
"I know the Mur very well, and after Evans accelerated halfway up and I was still at the front and in contention, I knew I had a good chance," added Rebellin. "In the last 200 metres I gave it everything, if I hadn't, I wouldn't have won."
The women's version of the race, run over a shorter 97.5km course, was won for the third consecutive time by Dutch champion Marianne Vos, ahead of Emma Johansson and Claudia Hausler.
Britain's Nicole Cooke finished in sixth place in the event, which forms part of the World Cup series.
"It was an interesting race with a lot of different developments," said Cooke. "I was happy with how I rode tactically but I just didn't have the legs to match [Marianne] Vos in the finale.
"The team rode well and I'm pleased with their performance."
The other British riders to finish were Catherine Hare in 18th place and Lizzie Armitstead in 22nd.
Fleche Wallonne men's results:
1. Davide Rebellin (Ita/Diquigiovanni) 4hrs 42mins 15secs
2. Andy Schleck (Lux/Saxo Bank) @ 2secs
3. Damiano Cunego (Ita/Lampre) @ st
4. Samuel Sanchez (Spa/Euskaltel) @ 7secs
5. Cadel Evans (Aus/Silence-Lotto) @ st
6. Thomas Lovkvist (Swe/Columbia) @ st
7. Alejandro Valverde (Spa/Caisse d'Epargne) @ 11secs
8. Simon Gerrans (Aus/Cervelo) @ st
9. Michael Albasini (Swi/Columbia) @ st
10. Rinaldo Nocentini (Ita/AG2R) @ 15secs
34. Chris Froome (GB/Barloworld) @ 43 secs
72. Daniel Fleeman (GB/Cervelo) @ 2min 55secs
84. Ben Swift (GB/Katusha) @ 3mins 6secs
92. Steven Cummings (GB/Barloworld) @ 3mins 9secs
Fleche Wallonne women's results:
1. Marianne Vos (Ned/DSB Bank) 2hrs 35mins 40secs
2. Emma Johansson (Swe/Red Sun) @ 6secs
3. Claudia Häusler (Ger/Cervelo TestTeam) @ 10secs
4. Amber Neben (USA/Equipe Nürnberger) @ 15secs
5. Noemi Cantele (Ita/Bigla Cycling Team)@ 20secs
6. Nicole Cooke (GB/Vision 1 Racing) @ 21secs
7. Mara Abbott (USA/Columbia) @ 22secs
8. Christiane Soeder (Aut/Cervelo TestTeam) @ 28secs
9. Loes Gunnewijk (Ned/Team Flexpoint) @ 31secs
10. Marta Vila Josana Andreu (Spa/Team Cmax Dila') @ 33secs
18. Catherine Hare (GB/Fenixs) @ 48secs
22. Lizzie Armitstead (GB/Lotto-Belisol) @ 1min 5secs