It was just a matter of time, but Conor McGregor has finally been sued by a UFC fighter for that April bus attack at Barclay's Center where he threw a steel dolly through a window, injuring several people.

The man behind the first lawsuit is Michael Chiesa -- who was scheduled to fight Anthony Pettis at UFC 223 but was forced to pull out due to the injuries he received in the bus attack

As we previously reported, Chiesa was on the bus with several fighters and UFC staffers when Conor and his gang of hooligans went berserk. Chiesa suffered cuts to his body and face.

CONOR SMASHING THE BUS
TMZSports.com

According to the lawsuit filed in state court in New York, Chiesa says he also suffered "severe emotional distress, mental trauma and/or bodily harm."

Chiesa is suing McGregor for assault, battery and intentional infliction of emotional distress. 

He's also going after the Barclay's Center for negligence, claiming they failed "to engage in proper security measures to protect the plaintiff and other patrons."

Chiesa doesn't specify how much he's going after in the suit -- but he's clearly looking for a big number because part of the damages he's seeking are the paychecks he lost due to missing that massive UFC event.

Conor was arrested after the incident and charged with felony criminal mischief and 3 counts of misdemeanor assault. However, he later struck a plea deal with prosecutors in which he pled guilty to misdemeanor disorderly conduct and the other counts (including the felony) were dropped. 

Conor issued a statement thanking the D.A. for "allowing me to move forward."

There were other fighters injured in the attack including Rose Namajunas who has also told the media she was emotionally scarred. She hasn't sued yet, but that's only a matter of time. 

Good thing Conor's rich ...