How could Iran win the 1941 Anglo Soviet invasion of Iran in 1941?

Iran was overwhelmingly outnumbered and inferior to Britain and USSR and stood no chance of winning in 1941.

To give a background Iran was decisiely defeated as early as 1857 by a British private company using a LARGELY private INDIAN Army and forced to withdraw from Afghanistan.

Thereafter Iran was a British Vassal and about 1907 was divided in two zones by Britain and Russia.

In WW 1 again Iran was invaded by British Indian Army and many of its major cities occupied.

Politically Iran was a British vassal since almost 1857.