Belisarius' forces consisted of about 20,000 men and another 5,000 Ghassanid Arab allies, who had been marching down the road leading into the heart of Persian territory along the right bank of the Euphrates in what today would be northern Iraq, then the eastern borders between the Roman Empire and Persia. The retreating Persian forces numbered about 15,000 and an additional group of Lakhmid Arabs. After several days of forced march, the Persians turned and deployed for battle.
Both groups formed up differently, Belisarius again choosing an "odd" formation that confused his opposing general. In this case he anchored his left flank on the bank of the river with infantry, put the Ghassanid Arab allies on the right flank, and placed several ranks of heavy cavalry, the cataphracts, in the center of the front line. In more standard formation the Persians split their forces into two roughly equal groups, with infantry in front of cavalry.
The Persians broke through the Roman right flank, forcing Belisarius to retreat in an effort to re-form his line, but the retreat was followed and soon the Romans found themselves pressed against the river. Here, the Romans were able to resist the Persians and withdraw much of their army across the river. The Persians chose not to follow up this victory, and returned to their withdrawal from Roman territory.