The battle started before all units were fully deployed. At 4:00 am on 11 September 1683, the Ottomans attacked, seeking to interfere with the deployment of Holy League troops.^[16]:661 The Germans were the first to strike back. Charles of Lorraine moved forward with the imperial army on the left and other imperial forces in the center and, after heavy fighting and multiple Ottoman counterattacks, took several key positions, specifically the fortified villages of Nussdorf and Heiligenstadt. By noon the imperial army had already severely mauled the Ottomans and come close to a breakthrough.^[29] Though shattered, the Ottoman army did not crumble at that moment.^[30]

Mustafa Pasha launched his counterattacks with most of his force, but held back some of the elite Janissary and Sipahi units for a simultaneous assault on the city. The Ottoman commanders had intended to take Vienna before Sobieski arrived, but time ran out. Their sappers had prepared a large, final detonation under the Löbelbastei^[31] to breach the walls. In total, ten mines were set to explode, but they were located by the defenders and disarmed.In the early afternoon a great battle started on the other side of the battlefield as the Polish infantry advanced on the Ottoman right flank. Instead of concentrating on the battle with the relief army, the Ottomans continued their efforts to force their way into the city. That meant the Poles could make good progress, and by 4:00 pm they had taken the village of Gersthof, which would serve as a base for their massive cavalry charge.^[15] The Ottomans were in a desperate position, between Polish and Imperial forces. Charles of Lorraine and John III Sobieski both decided, on their own, to continue the offensive and finish off the enemyThe imperial forces resumed the offensive on the left front at 3:30 pm. At first they encountered fierce resistance and were stopped. This did not last long, however, and by 5:00 pm they had made further gains and taken the villages of Unterdöbling and Oberdöbling. They were now very close to the central Ottoman position (the "Türkenschanze").^[30] As they were preparing to storm it, they could see the Polish cavalry in actionIt is recorded that the Polish cavalry slowly emerged from the forest to the cheers of the onlooking infantry, which had been anticipating their arrival. At 4:00 pm the hussars first entered into action, battering the Ottoman lines and approaching the Türkenschanze, which was now threatened from three sides (the Poles from the west, the Saxons and the Bavarians from the northwest and the Austrians from the north). At that point the Ottoman vizier decided to leave this position and retreat to his headquarters in the main camp further south. However, by then many Ottomans were already leaving the battlefield.^[15]

The allies were now ready for the last blow. At around 6:00 pm the Polish king ordered the cavalry attack in four groups, three Polish and one from the Holy Roman Empire—18,000 horsemen charged down the hills, the largest cavalry charge in history.^[32][33] Sobieski led the charge^[16]:661 at the head of 3,000 Polish heavy lancers, the famed "Winged Hussars". The Muslim Lipka Tatars who fought on the Polish side wore a sprig of straw in their helmets to distinguish them from the Tatars fighting on the Ottoman side.^[34] The charge easily broke the lines of the Ottomans, who were exhausted and demoralized and soon started to flee the battlefield. The cavalry headed straight for the Ottoman camps and Kara Mustafa's headquarters, while the remaining Viennese garrison sallied out of its defenses to join in the assault.^[16]:661The Ottoman troops were tired and dispirited following the failure of the attempt at sapping, the assault on the city and the advance of the Holy League infantry on the Türkenschanze.^[16]:661 The cavalry charge was the final deadly blow. Less than three hours after the cavalry attack, the Catholic Christian forces had won the battle and saved Vienna. The first Catholic Christian officer who entered Vienna was Louis William, Margrave of Baden-Baden, at the head of his dragoons.^[15] Afterwards Sobieski paraphrased Julius Caesar's famous quotation (Veni, vidi, vici) by saying "Venimus, vidimus, Deus vicit"- "We came, we saw, God conquered".^[1