Having plundered and completely destroyed Tigranakert, Lucullus decided to seize the second capital of Armenia, Artashat, and thereby redeployed his troops to the north.
At the same time, Tigran II the Great and Mitridate VI del Ponto gathered and trained new troops. Tigran planned to apply new battle tactics as well.
According to them, avoiding large encounters, Armenian troops eliminated small Roman units in quick fights, obstructing the supply channels of the Romans. These new tactics exhausted the Romans but did not manage to stop them completely.
Lucullus stubbornly carried on advancing with his worn-out soldiers, cheering them with the perspective of unseen wealth awaiting them in the “Armenian Carthage”, Artashat.
The threat of Artashat’s seizure forced Tigran to confront the Romans in a major battle, which took place near the crossing of the Aratsani river in September, 68 BC. The well-trained and organized Armenian army defeated the Romans, who suffered heavy losses and had to leave Armenia.
Cassius Dio writes in this regard, “In this battle, the enemy cavalry put the Romans’ in a difficult position. Because many were wounded and some fell, not to mention the groans of the injured soldiers, Lucullus retreated…”
To further enforce their success, Armenians drove the Romans out of the southern areas of Armenia, including Mesopotamia. Moreover, Mitridate along with Armenian units invaded Pontus and won back his own kingdom.
Although the Romans simply refused to fight against both Tigran and Mitridate, the united Armenian-Pontic troops forced them to battle. Yet again, the Roman legions were defeated. And the dissatisfied Roman Senate would then dismiss Lucullus.