With the fall of Guadalcanal, Japan was presented with a stunning setback. For the first time in the war, the Imperial military had been defeated decisively on the ground, in the air, and on the sea. Now it would have to shift its stance from the offense to the defense, as the ever-strengthening Allied forces began pushing their way up the Slot towards Rabaul. For the Americans, difficult fighting still lay ahead, and they would suffer several more tactical defeats at the hands of the Japanese Navy as the battles in the Solomons continued. Yet with the victory at Guadalcanal, both combatants recognized that the momentum of the Pacific war had shifted decisively in the Allies favor.