On 21 February 1943, Campbell was escorting the 48-ship convoy ON 166 when the convoy was surrounded by a U-boat "wolf pack". and torpedoed and sank whale factory ship N.T. Nielsen Alonso. Dispatched to assist, Campbell rescued fifty survivors and then turned to attack U-753, damaging it so badly that it had to withdraw. Throughout 21 and 22 February, Campbell attacked several U-boats, inflicting damage and driving them off. Later on 22 February, , having sustained heavy damage inflicted by the Polish destroyer , surfaced in the midst of the convoy attempting a surface attack. Campbell struck the U-boat a glancing blow that gashed Campbells hull in the engine room below the waterline, but continued to attack, dropping two depth charges which exploded and lifted the U-boat out of the water. The crew brought all guns to bear on the U-boat, fighting on until water in the engine room shorted out all electricity. As the ship lost power and the searchlights illuminating the U-boat went out, the U-boat's commander ordered the vessel abandoned. Campbell ceased fire and lowered boats to rescue the U-boat's survivors. Campbell, disabled in the attack, was towed to port nine days later, repaired and returned to escort duty.
