The landing splits the Japanese defense

The Third Marine Division landed between the Japanese Seventeenth Army's stronger northern and southern concentrations. Task Force 39 supplied shore fire support and protection against surface attack, while nearby Allied aircraft could oppose raids from Rabaul. Omori hoped to repeat the Japanese success at Savo Island in August 1942, but Merrill's cruisers and destroyers had practiced and operated together. Twelve American transports departed at 18:00, leaving four cargo vessels still unloading; the minelaying force also withdrew. Reconnaissance located Omori and allowed Merrill to leave bombardment duties, sail around Vella Lavella, and intercept the Japanese force before it reached Cape Torokina. Japanese maintenance shortages reduced sustained cruising speed even where ships could still reach high speed briefly, helping the Americans arrive first.