The final assault allegedly occurred in December 2016 as Bell and Pendley ate dinner with Tech's basketball team before a game at Tennessee.
Before Georgia Tech, Pastner, 40, coached at Memphis from 2009-16.
Thursday's suit comes one month after Pastner filed an defamation suit, claiming the couple repeatedly attempted to blackmail and extort him.
"But unequivocally, zero, zero, zero, zero, zero, zero truth to any of those disgusting, bogus allegations".
Pastner's attorney, Scott Tompsett, has since released a statement vehemently denying the accusations against his client.
11Alive normally does not name sexual assault victims, but is doing so because Pendley and Bell have chosen to make the case public. "It is a lie".
He called Bell "a career criminal" who concocted the complaint "as a last-ditch effort to continue an extortion and blackmail scheme that failed".
Pendley reported the alleged assault to her doctor a year later, the suit states, and the doctor subsequently referred her to a counselor and psychiatrist.
Georgia Tech coach Josh Pastner is the target of a sexual assault lawsuit. The lawsuit filed today is a counter-suit to that defamation suit. Bell and Pastner had developed a close relationship since Bell got out of prison. However, Pastner identified Pendley in his lawsuit and she did not file her response anonymously. While Bell was getting food, the court papers said, Pastner "ran his hand up and down Pendley's leg" beneath the table and then reached between her legs.
The counterclaim goes on to say that there were 11 alleged occasions where Pastner sexually harassed Pendley between February 14, 2016 and March 3, 2016. The lawsuit says a security guard witnessed the incident.
Pendley said that as she sat on the bed, Pastner stood in front of her and began stroking her hair. Pendley became upset and ran to a restroom, and the security guard asked if she was OK when she came out. It also pointed to a Oro Valley Police report in which officers investigated alleged abuse by Bell against Pendley, and claims that Bell's own family took protective measures against him. She said she resisted, but Bell could not hear her crying from the bathroom.
Tompsett's statement claims Bell has a "history of abusive, manipulative and controlling behavior toward women".