Mareli Miniutti wrote in a sworn statement that during the argument, Avenatti shouted expletives at her and told her she was "ungrateful" before he hit her in the face with pillows. She said Avenatti attempted to pull her out of a bed in his guest bedroom and snatched her phone away before she screamed for help.
Avenatti, who was arrested last week on a felony domestic violence charge, called the allegations "completely false." He's scheduled to appear in court next month.
Avenatti, who is mulling a presidential run, is best known as the attorney for porn actress Stormy Daniels, who has said she had an affair with President Donald Trump in 2006, a claim Trump denies. As Daniels' lawyer, Avenatti has pursued the president and those close to him relentlessly for months, taunting Trump in interviews and baiting him and his lawyers in tweets.
Asked about Avenatti's arrest, Trump said Tuesday, "I wish him the best of luck."
In her request for a restraining order against Avenatti, Miniutti said she was wearing only a T-shirt and underpants when he grabbed her by the arm and dragged her out of the bed. The order was granted Monday.
She said she was scratched on her side and leg. Court papers include photographs that appear to show bruises.
Miniutti said she eventually ran back into the bedroom, put on pants and ran to a service elevator, riding to the lobby with Avenatti. A friend picked her up and took her to the friend's home, where she called Los Angeles police.
Avenatti was released on $50,000 bail after his arrest last Wednesday. Prosecutors have not formally filed charges.
Avenatti's lawyers sent a letter to Los Angeles detectives Monday that said he didn't inflict any injuries and had never been physically confrontational with anyone. The letter was provided to the AP by a person familiar with the investigation who requested anonymity because of the sensitivity of the situation.
In a statement, Avenatti said: "There is extensive evidence that demonstrates that these allegations are fabricated, including multiple security cameras. I will be fully vindicated when all of this is said and done."
He has also called for his apartment building to release surveillance video that he says would support his claims, even though the violence described by Miniutti would not have occurred in the building's public areas.
Miniutti said this was the second such incident between her and Avenatti. She said Avenatti in February pushed her out of another apartment they were sharing into a hallway, where she struck her head against a door.
She described Avenatti as "verbally abusive and financially controlling."