When generals lose unsustainable numbers of soldier even they win the battle was called rome?

A Pyrrhic victory

The name comes from King Pyrrhus of Epirus (an ancient Greek state, on the northwestern part of the Greek peninsula).  At the battles of Heraclea (280 BC) and Asculumin (279 BC), Pyrrhus defeated the Romans but did so with massive casualty counts.  The Romans also suffered large numbers of casualties, but they had more men they could bring to replace them, where Pyrrhus did not.  So by 275 BC, Rome was able to win the Pyrrhic War.