I have heard people refer to Alexander the Great as one of the greatest military commanders of all time because he was "undefeated in battle" during his lifetime. Is this true? I can imagine him winning every war that he fought but to win every battle seems like an incredible feat. Do we know of any individual battles that he outright lost?
If Alexander the Great is labelled as "one of the greatest military commanders of all time" is not because he wasn't defeated, but because his conquests.
Having said that, yes, it's true: there's no single defeat recorded for Alexander.
It can be argued the primary sources about his life were not impartial, but the Battle of Hydaspes river is recorded as a decisive victory for the Macedonians, not even a "Pyrrhic" victory.
Alexander's troops mutinied at the Hyphasis river because exhaustion at the prospects of campaigning for eight years more, as Alexander (at first) had no intentions of turning back.
But even if Alexander lost a battle anywhere, that wouldn't make of him a less better commander. Most commanders wearing the "undefeated" badge could choose to fight or not to fight (Davout and Suvorov come to mind). Others simply could not afford that luxury.
By what rubric are we measuring greatest? Let's make no mistake, ALexander achieved some amazing victories - but were they the astoundingest ? Did he overcome the greatest tactical or strategic disadvantages? Where's the measurements? Territory conquered?
At any rate, the one to me that was always the most portentous, (and some might dispute this rather oblique, sleep deprived, wine fueled answer.)
The Gordian Knot.