Prolonging Michael with the drive west delayed and weakened the attack in Flanders. Again they broke through, smashing the Portuguese defenders and forcing the British from all of the ground they had paid so dearly for in 1917. However, French support enabled the British to save Hazebrouck, the rail junction that was the German goal. To draw the French reserves away from Flanders, the next attack was along the Aisne River where Nivelle had attacked the year before. Their success was dazzling. The defender's front was immersed in a gas cloud fired from simple mortars, within hours they had reoccupied all the ground the French had taken by weeks of grinding, and they continued to sweep south through Champagne until they halted for resupply at the Marne River.