Why were the Polish-Lithuanian army able to defeat the crusaders?

In 1410, a major battle took place between the Teutonic Order on the one hand and the Lithuanian-Russian principality and Poland on the other. The battle took place at Grunwald. It was a decisive battle in which both sides fielded large forces. The battle was won thanks to the resilience of the Russian regiments, which held back the onslaught of the Teutons. Ultimately, the troops of the Teutonic Order were defeated. In this connection, the decline of the Teutonic Order soon occurs.