The engagement began with first contacts being made about 1 pm. There were no established front lines and neither side had many units involved at the beginning. The nature of the action was an encounter battle with troops being fed onto the battlefield as and when they were ready or needed. The key was the Allies drawing in the French to the centre [about 5.30 pm] and then producing powerful pincer movements on both flanks [7.30 to 8.30 pm]. The French were utterly defeated and many troops only got away because of the approaching darkness and the Allied fear of firing on one another.
This was Marlborough's greatest feat of generalship, his eye for the ground, his sense of timing, his ability to respond to his opponents moves, his knowledge of his opponents likely actions, his careful use of his resources and his willingness to rely on good subordinates all contributed to this success.