Harden's downtown bomb came with about 3:24 remaining in the 115-104 win Sunday at TD Garden in Boston. The "Beard" scored a game-high 42 points in the win. Irving had 24 points to lead the Celtics.
The Rockets led 109-100 when Harden had the ball during the fourth quarter sequence. He eyed Irving beyond the 3-point line before the Celtics star closed in on him defensively. Harden did several crossovers before picking up his dribble and doing his signature step-back move.
Jayson Tatum joined Irving in an attempt to defend Harden, but it didn't matter. The "Beard" fired up a long distance heave, while possibly getting fouled by Irving. The ball floated toward the rim before sinking through the net, giving the Rockets a 12-point lead down the stretch.
"It's [the step-back] just giving more opportunities and more space to get my shot off, and have defenders to close the gap on me to get by you, so you've got to pick and choose," Harden told reporters.
The Rockets face the Toronto Raptors at 8 p.m. Tuesday at Scotiabank Arena in Toronto.