The duel with Albert King occurs in the course of the main story. He is one of the Joker Infected whom you have to apprehend once more during one of later visits in Panessa Studios. He is located in the sound stage A.
A duel with a mini-boss, Albert King, awaits you. He is not difficult to beat, although you have to follow a few step procedure to gradually lower his health bar displayed in the right top corner of the screen. After you start the combat, do not try to attack King and if possible stay away from him, so to avoid getting Batman or Robin hurt. Instead, focus on his thugs, jumping from one to another to increase the multiplier.
Keep hitting the ordinary bandits until you can launch a Team Attack. Use this as soon as possible - the attack will be automatically aimed at Albert King. Repeat these steps, i.e. knock down the ordinary thugs and perform Team Attacks against the boss.
In the next part of the duel, after launching a Team Attack you will be able to deliver a series of quick strikes resembling a classic Beatdown. Keep pressing the attack key/button. Be ready to counter the boss's attacks by pressing the counter button, when he tries to break free and strike you back. The duel is over when King's health bar drops to zero.