Sertorius (21.5-21.6)

Then, when the cities sent their messengers, he cut his way through the enemy with no trouble and effected a junction with his new troops; and so once more he advanced upon the enemy with large reinforcements and began to cut off their land supplies by means of ambuscades, flank movements, and swift marches in every direction, and their maritime supplies by besetting the coast with piratical craft; so that the Roman generals were compelled to separate, Metellus retiring into Gaul, and Pompey spending the winter among the Vaccaci. Here he suffered much from lack of supplies, and wrote to the senate that he would bring his army home unless they sent him money, since he had already exhausted his own resources in his war for the defence of Italy.[*]

Indeed, this story was prevalent in Rome, that Sertorius would come back to Italy before Pompey did. To such straits were the first and ablest generals of the time reduced by the skill of Sertorius.