Providing a boost for Europe ahead of this week’s Ryder Cup, McIlroy held his nerve in a dramatic three-way play-off tussle with American duo Kevin Chappell and Ryan Moore at East Lake, needing a fourth crack at the latter before a birdie at the 16th settled matters.
A superb back nine for McIlroy, which included an incredible eagle at the par-four 16th, capped a six-under-par 64 and forced a play-off as Chappell missed a tough birdie putt at 18 which could have settled matters and handed Johnson the FedEx Cup.
As McIlroy soared, Johnson wilted. Johnson started the day with his destiny in is own hands but his share of the lead dissipated as the 32-year-old fired a 73, including a double bogey at 12, to finish tied for sixth on five under.
England’s Paul Casey, meanwhile, maintained his impressive form as he finished fourth on nine under.