"Invincible"s first action was as part of the battlecruiser force under the command of Admiral Beatty during the Battle of Heligoland Bight operation on 28 August 1914. Beatty's ships had originally been intended as distant support of the British cruisers and destroyers closer to the German coast in case large units of the High Seas Fleet sortied in response to the British attacks. They turned south at full speed at 11:35 when the British light forces failed to disengage on schedule and the rising tide meant that German capital ships would be able to clear the bar at the mouth of the Jade estuary. The brand-new light cruiser had been crippled earlier in the battle and was under fire from the German light cruisers and when Beatty's battlecruisers loomed out of the mist at 12:37. "Strassburg" was able to duck into the mists and evade fire, but "Cöln" remained visible and was quickly crippled by fire from the squadron. Beatty was distracted from the task of finishing her off by the sudden appearance of the elderly light cruiser directly to his front. He turned in pursuit and reduced her to a flaming hulk in only three salvos at close range (under ). At 13:10, Beatty turned north and made a general signal to retire. At this time, "Invincible", trailing the main body of battlecruisers, opened fire on "Cöln". She fired 18 rounds, all misses, before Beatty's main body encountered the crippled "Cöln" shortly after turning north and she was sunk by two salvos from .