His subject was "a typical French poilu" or infantryman. The man was the driver who had brought Australian prime minister Billy Hughes and his deputy, Joseph Cook, to Monash's headquarters the day before.

To the east, the sounds of battle filled the air. Almost 15,000 Australians, Americans, British and Germans were locked in mortal combat. The Allied attack on the French village Hamel, which had brought together dozens of planes, hundreds of artillery pieces, about 60 heavy tanks and 8000 Australian and American infantrymen, was under way.

Later that day, Monash would send the finished sketch to his wife, Victoria, in Melbourne: "As you like my previous sketch, I send you another one; it was done ... while the battle of Hamel, which we have just won, was at its height," he wrote. "When once a commander's orders are issued, there is little for him to do but wait and watch and I find this occupation keeps my nerves cool and steady."

The citizen soldier, who remains as controversial today, 87 years after his death in 1931, as he was at the height of his fame, would have had a lot on his mind that summer morning.

Monash had been named head of the Australian Army Corps, taking over from General Sir William Birdwood, and promoted to lieutenant-general, just over a month before. It was an achievement of which he was very proud, a fact he did not conceal in a letter to Victoria dated May 31.

"My new command comprises a total at present of 166,000 troops and covers practically the whole Australian field army in France ... at long last the Australian nation has achieved its ambition of having its own commander-in-chief, a native born Australian – for the first time in history."

Not all his soldiers were Australian. There were 1000 American engineers and 50,000 British troops: 25,000 regulars and 25,000 "new army". The British contingent included two royal horse artillery brigades.

While there were no tanks, Monash, a trained engineer who understood the importance of innovation and technology in battle, did have his own small air force.

"My flying squadron is wholly Australian and is one of the most efficient squadrons in France," he wrote. "Its 20 aeroplanes do all my air reconnaissances, photography and counter-battery work ..."

The freshly minted lieutenant general was keen to put his new instrument to the test. Monash drew on all its elements, along with about 60 of the latest Mark V tanks from the British Tank Corps, for the Battle of Hamel: the first action planned by him as Australian Corps commander and the first clear test of his abilities to lead at this level.

While the story of the fight, a relatively small affair in terms of duration and the number of men engaged by the standards of the Western Front, has been told many times, repetition should not rob Hamel of its significance.

Monash had planned meticulously to achieve total surprise; the one element that had been lost over four years of trench warfare. He did this by mounting what was arguably the war's first truly combined-services operation.

Notable firsts included the "conditioning" of the German forces to expect a gas attack, the use of low-flying planes to mask the sounds of the 29-tonne tanks being marshalled for the assault and the use of the RAF to drop ammunition to the Australian machine-gunners while the battle raged.

All of these elements, including the historic combat debut of American forces in France on their nation's Independence Day, came together in a way extremely rare in the fog of war.

"With the noise [of the aircraft] drowning the sound of the tank movements, by the time the Germans knew they were being invaded, the vehicles were just metres away and emerging from the fog like monsters. Those Germans who didn't freeze were flattened, chased or fought by the tanks and the supporting infantry ... it was a rout," Roland Perry wrote in Monash: The Outsider Who Won The War.

Historian and military theorist Captain Liddell Hart described Hamel as a "brilliant little surprise coup with tanks".

The Australian triumph was a major step on the road to August 8, 1918, Erich Ludendorff's "black day for the German army" that was so important in bringing the years of slaughter to an end.

That was when Field Marshall Douglas Haig unleashed the massive attack against the German positions to the east of Amiens that destroyed the German army's morale.

"Haig designed some local moves to improve his position. His immediate concern was to free the railways east of Amiens," historian A. J. P. Taylor wrote. "Canadian forces were moved secretly, quite in the new German way. They were aided by the Australians, who possessed in Sir John Monash the only general of creative originality produced by the First World War."

Monash, whose victory at Hamel had contributed greatly to the template for the Amiens offensive, was elated by the result. He was too busy to write to Victoria until August 11.

"It was from it [Villers-Bretonneux] that we launched the great attack of August 8, which has been so brilliantly successful and which has carried our front line some 10 miles [16 kilometres] eastward ... Villers-Bretonneux is now headquarters of the 1st Australian Division, while the 2nd Australian Division has its headquarters on the western outskirts of it.

"[All around Villers-Bretonneux on the afternoon of August 8] was a scene of the greatest activity. On one side of the main road was a large wired-in prisoners' cage in which were over 3000 prisoners captured during the last 24-hours ... An immense stream of traffic was pouring up the road towards the front, guns, troops, strings of horses and mules, hundreds of motor lorries, ambulance wagons and the usual motley traffic of war."

Three days later, Monash wrote to Victoria again: he had received a visit from King George V at his headquarters at Bertangles Chateau. The Monarch had invested the General with the knighthood that had been announced in the New Year's Day honours list at the start of the year.

There is some debate as to whether or not Monash was the first British military commander to be invested with a knighhood in the field in more than two centuries.

"A square of carpet had been arranged in the centre of the piazza and on it stood a small table, a footstool, and a drawn sword. The king then had my name called and I stepped up before him and, at his behest, knelt and received the accolade of knighthood ... He shook hands most warmly and made me a little speech, commending my work and that of the Australian troops."

It was the culmination of a brilliant career.