After being troubled in the opening round against the Polish heavyweight, Chisora responded superbly in the second, landing a chilling right hook on his opponent.
Szpilka's gloves were already down when Chisora landed a second huge hook that send him to the mat.
Chisora now hopes to secure a meeting with former WBO heavyweight champion Joseph Parker and force one last foray into the heavyweight title scene.
Szpilka, a former world title challenger, arguably nicked that opening round, but he quickly succumbed to Chisora's sheer power.
The home favourite landed an enormous right hook that left his southpaw opponent reeling towards the ropes.
Chisora then sank a couple of hard body shots before switching back upstairs with two sickening blows - the final shot another colossal right that sends Szpilka sinking to the canvas.
Szpilka challenged for Deontay Wilder's WBC title in 2016, stopped in the ninth round against the American.
Chisora took considerably less time to secure an early candidate for knockout of the night.