In 86 BC, after Sulla's victory in Orchomenos, he initially spent some time re-establishing Roman authority. His legate soon arrived with the fleet he was sent to gather, and Sulla was ready to recapture lost Greek islands before crossing into Asia Minor. The second Roman army under the command of Flaccus meanwhile moved through Macedonia and into Asia Minor. After the capture of Philippi, remaining Mithridatic forces crossed the Hellspont away from the Romans. The Romans, under Flaccus' subordinate C. Flavius Fimbria, were encouraged to loot and create general havoc as it went, creating problems between Flaccus and Fimbria. Flaccus was a fairly strict disciplinarian and the behavior of his lieutenant led to discord between the two.
At some point as this army crossed the Hellspont while giving chase to Mithridates' forces, Fimbria seems to have started a rebellion against Flaccus. While seemingly minor enough to not cause immediate repercussions in the field, Fimbria was relieved of his duty and ordered back to Rome. The return trip included a stop at the port city of Byzantium, however, and here Fimbria took command of the garrison, rather than continue home. Flaccus, hearing of this, marched his army to Byzantium to put a stop to the rebellion, but walked right into his own undoing. The army preferred Fimbria (not surprising considering his leniency in regard to plunder) and a general revolt ensued. Flaccus attempted to flee, but was captured shortly after and the rightful Consular commander was executed. With Flaccus out of the way, Fimbria took complete command.
The following year (85 BC) Fimbria took the fight to Mithridates while Sulla continued to operate on the Greek Islands of the Aegaeum. Fimbria quickly won a decisive victory over remaining Mithridatic forces and moved on the capital of Pergamum. With all vestige of hope crumbling for Mithridates, he fled Pergamum to the coastal city of Pitane. Fimbria was in hot pursuit, laying siege to the town, but knowing he couldn't prevent Mithridates' escape by sea. Fimbria called upon Sulla's legate, Lucullus to bring his fleet around to block Mithridates in, but it seems that Sulla had other plans.
Sulla apparently had been in private negotiation with Mithridates to end the war. He wanted to develop easy terms and get the ordeal over as quickly as possible. The quicker it was dealt with, the faster he would be able to settle political matters in Rome. With this in mind, Lucullus and his navy refused to help Fimbria, and Mithridates 'escaped' to Lesbos. Later at Dardanus, Sulla and Mithridates met personally to negotiate terms. With Fimbria re-establishing Roman hegemony over the cities of Asia Minor, Mithridates position was completely untenable. Yet Sulla, with his eyes on Rome, offered uncharacteristically mild terms. Mithridates was forced to give up all his conquests (which Sulla and Fimbria had already managed to take back by force), surrender any Roman prisoners, provide a 70 ship fleet to Sulla along with supplies, and pay a tribute of 2,000 to 3,000 gold talents. In exchange, Mithridates was able to keep his original kingdom and territory and regain his title of "friend of the Roman people."
For all intensive purposes, Sulla's settlement made it seem as if the war had never happened. He used his victory to gain supplies and money to seemingly finance his coming expedition back to Rome, while Mithridates suffered little for his actions. It's still difficult to determine Sulla's exact mindset however. There is evidence that he was still in some sort of loose contact with the Senate despite his declaration as an enemy of the Roman state. Magistrates, especially ones favorable to Sulla, were still being elected in Rome and sent east to govern without interference. Depsite Sulla's later claims, Rome under Cinna was relatively calm and the full Senate seemed to participate in legislation and debate. Perhaps as long as Sulla had his legions, the Senate would not act, but it didn't really do anything to counter Sulla's command even from an insubstantial legal standpoint.
But things in the east weren't yet settled. Fimbria was enjoying free reign in the province of Asia and led a cruel oppression of both those who were involved against Romans, and those who were now in support of Sulla. Unable to leave a potentially dangerous army in his rear, Sulla crossed into Asia. He pursued Fimbria to his camp at Thyatira where Fimbria was confident in his ability to repulse an attack. Fimbria, however, soon found that his men wanted nothing to do with opposing Sulla and many deserted or refused to fight in the coming battle. Sensing all was lost, Fimbria surrendered by taking his own life, while his army went over to Sulla.
To ensure the loyalty of both Fimbria's troops and his own veterans, who weren't happy about the easy treatment of their enemy, Mithridates, Sulla now started to penalize the province of Asia. His veterans were scattered throughout the province and allowed to extort the wealth of local communities. Large fines were placed on the province for lost taxes during their rebellion and the cost of the war. With his army gaining their unorthodox method of 'plunder', it wouldn't be long before Sulla would make his next move.
As the year 84 BC rolled in, Cinna, still Consul in Rome, was faced with minor disturbances among Illyrian tribes. Perhaps in an attmept to gain experience for an army to act as a counter to Sulla's forces, or to show Sulla that the Senate also had some strength of its own, Cinna raised an army to deal with this Illyrian problem. Conveniently the source of the disturbance was located directly between Sulla and another march on Rome. Cinna pushed his men hard to move to position in Illyria and forced marches through snow covered mountains did little to endear Cinna to his army. A short time after departing Rome, Cinna was stoned to death by his own men and history was about to take another fateful step. Hearing of Cinna's death, and the ensuing power gap in Rome, Sulla gathered his forces and prepared for a second march on the capital.