Which battle was the turning point that gave Julius Caesar victory in Rome’s civil war?

The Battle of Pharsalus was a decisive battle of Caesar's Civil War. On 9 August 48 BC at Pharsalus in central Greece, Gaius Julius Caesar and his allies formed up opposite the army of the republic under the command of Gnaeus Pompeius Magnus ("Pompey the Great"). Pompey had the backing of a majority of the senators, of whom many were optimates, and his army significantly outnumbered the veteran Caesarian legions.

The two armies confronted each other over several months of uncertainty, Caesar being in a much weaker position than Pompey. The former found himself isolated in a hostile country with only 22,000 men and short of provisions, while on the other side of the river he was faced by Pompey with an army about twice as large in number. Pompey wanted to delay, knowing the enemy would eventually surrender from hunger and exhaustion. Pressured by the senators present and by his officers, he reluctantly engaged in battle and suffered an overwhelming defeat.