The war wasn't won in 1941, early 42, it was just "not lost"; big difference. Anyway, the Russians WERE receiving lend lease prior to and at the time of Stalingrad. They didn't do it on their own, and would have lost had it not been for the Western capitalism Russia spent the next 60 years trying to destroy.
One Russian soldier was given a gun, his buddy was given 3 bullets. This against fully equipped Germans with tanks and air dominance.
To belittle their winning role is sheer arrogance on your part.