Kerr has been in sensational form of late, leading the NWSL scoring charts with 15 goals in 16 starts, and becoming one of ten players nominated for the upcoming Best FIFA Women's Player 2017 award.
Sky Blue were down 3-0 at half-time before Kerr led the improbable comeback starting in the 48th minute when she prodded home a loose ball in the penalty area with her right foot.
The 23 year-old then put her team within one in the 68th minute, sprinting on to a long diagonal pass before striking the ball across the goalkeeper and into the bottom corner.
Just three minutes later, Kerr made it a hat-trick with a stunning solo effort. Controlling the ball with her chest on the half-way line, the Fremantle-born striker had Seattle's defence back-peddling as she sprinted towards goal.
The Seattle defenders backed off and as Kerr reached the edge of the box she curled the ball into the top-right corner of the goal.
It looked like all Kerr's brilliance had been undone when Kiersten Dallstream made it 4-3 to Seattle with just five minutes remaining.
However, Sky Blue somehow manage to pull a rabbit out of the hat, with Maya Hayes equalising in the 92nd minute with Kerr involved in the build up, before the Matildas striker clinched the late winner making it 5-4 in the 94th minute.
A final hopeful corner was swung into the box as Kerr timed her run to perfection before heading a looping header over the defender on the front post and into the goal.
The Perth Glory striker was swamped by teammates as she secured her side the three points and further pushed her claim for best female player in the world.