The sister of tragic high-school basketball star Tayshana “Chicken” Murphy yesterday relived her final hours as she testified at the Manhattan murder trial of the two men accused of fatally shooting the innocent bystander.

“My sister talked me into coming downstairs with her awhile,” Tanasia Williams, 23, recalled as the first witness against accused shooter Tyshawn Brockington, 23, and alleged gun supplier Terique Collins, 25.

The sisters had laughed and danced that night in September 2011 in the dark courtyard of Harlem’s Grant Houses.

“Chicken,” 18, was a senior at Murry Bergtraum HS for Business Careers and was considered a top young hoopster.