Gebrselassie, who has a left Achilles injury, said he would have withdrawn from the event had it not been the Olympics.
His heir apparent and training partner Kenenisa Bekele looks almost certain to dethrone his mentor, just as he did at the 2003 World Championships, and Gebrselassie seems happy to help.
"The important thing is that Ethiopia wins ... for me, any medal would be fantastic," he said.
The other medal of the day comes in the opening event, when Ecuador's world champion and record holder Jefferson Perez launches his bid for a 20km-50km double.
Much of Friday will be dominated by the heptathlon and the 21-year-old
Moroccan Hicham El Guerrouj, who regards himself as the unluckiest athlete of modern times after being beaten to the 1,500 metres crown in Atlanta and Sydney, begins his attempt to win the title he most covets.
The women's 100 metres, which climaxes on Saturday, also begins. There will be no Marion Jones, the Sydney champion who failed to qualify, and no Kelli White in the heats.
There will be no Torri Edwards, like White caught up in doping, nor Greece's Katerina Thanou, who missed a drugs test in farcical circumstances on the eve of the Games.
There has never been a more scandal-ridden women's race in Olympic history, nor a more open one.
