In October 1942, VMF-121 pilots and aircraft were sent to Guadalcanal as part of Operation Watchtower to relieve VMF-223, which had been fighting for control of the air over the island since mid-August. On October 9, Foss and his group were catapult launched off the escort carrier and flew north to reach Guadalcanal. The air group, code named "Cactus", based at Henderson Field became known as the Cactus Air Force, and their presence played a pivotal role in the Battle of Guadalcanal. Foss soon gained a reputation for aggressive close-in fighter tactics and uncanny gunnery skills. Foss shot down a Japanese Zero on his first combat mission on October 13, but his own F4F Wildcat was shot up as well, and with a dead engine and three more Zeros on his tail, he landed at full speed, with no flaps and minimal control on Henderson Field, barely missing a grove of palm trees. On 7 November his Wildcat was again hit, and he survived a ditching in the sea off the island of Malaita.