It happened at a public park on the 1400 block of Hook Road around 4:00 p.m.
Police tell Action News both men were shot in the back.
One of the victims ran from the shooting scene and later showed up at the Hospital of the University of Pennsylvania where he is listed in critical condition.
The other man stumbled from the court to a nearby house. He was later taken to the hospital with non-life-threatening injuries.
Police are looking for at least two gunmen.
They believe the gunmen were watching the basketball game along with dozens of other spectators before they started shooting.
At 9:00 p.m. Sunday, Darby Township enacted a curfew.
This follows a state of emergency in Darby Borough that began Friday.