Gebrselassie, double Olympic 10,000m champion, clocked 27min 01sec in his comeback from a calf injury to break Kenyan Sammy Kipketer's previous record by 10 seconds.
In the women's race, fellow Ethiopian Derartu Tulu, the World and Olympic 10,000m champion, won in 32:23.
Compatriots Geta Wami and Kutre Dulecha finished second and third to complete a clean sweep for Ethiopia.
"
I would say I was at between
75 to 80 percent of the level I hope to achieve next year
"
Haile Gebrselassie
At 6.5 km, Gebrselassie made a break from the leading group, which included Kenyans Francis Kiprop and James Kipketer and fellow Ethiopians Worku Bikila and Hailu Mekkonen.
And once Gebrselassie took control, the race result and the record were never in doubt with the Ethiopian winning from Mekkonen and Kiprop.
"The first kilometre was a little bit fast and I was a little nervous but everything turned out so well, its really fantastic," said Gebrselassie.
"This race was to help me access my fitness and I am very pleased though I still need more speed. I would say I was at between 75 to 80% of the level I hope to achieve next year.
"This has been a fantastic result for my confidence, after my injury problems. My next race is likely to be indoors in Stuttgart."
Results:
Men
1. Haile Gebrselassie (Eth) 27:02 (world record)
2. Hailu
Mekonnen (Eth) 27:39
3. Francis Kiprop (Ken) 27:49
Women
1. Derartu Tulu (Eth) 32:23
2. Gete Wami (Eth) 32:27
3. Kutre
Dulecha (Eth) 32:29