[3] His handling of the corps during the August offensive, the Battle of Sari Bair warranted his replacement after only nine days with Lieutenant-General Julian Byng.

This sector was the unlucky target of the next German offensive, the Third Battle of the Aisne in May–June 1918, causing further losses to IX Corps.

General Denis Duchêne, commander of the French Sixth Army, had deployed IX Corps (five divisions) too far forward, on the Chemin des Dames ridge, which had been gained at such cost in the Second Battle of the Aisne the previous year.

(The French Commander-in-Chief Philippe Pétain and the Army Group Commander Franchet d’Esperey would have preferred the ridge to be lightly held and the main defence to be a battle zone between it and the River Aisne).

The IX Corps headquarters, with Brigadier Gordon MacMillan as its chief of staff, landed in and opened as the reserve for the Allied 18th Army Group on 24 March 1943.