Just weeks after Isabel Lucas escaped with minor injuries as a passenger in Shia LaBeouf's rollover DUI wreck, her relationship with "Entourage" swain Adrian Grenier has also crashed.

"It wasn't working out," a source tells People magazine. "Adrian saw her with Shia and that was kind of it -- the crash, their hanging out. He obviously didn't appreciate it." A rep for the Aussie actress confirmed to the mag that Isabel "is single."

LaBeouf flipped his Ford truck July 27 while his "Transformers 2" co-star Isabel was riding shotgun. Lucas, 22, and Grenier, 32, had reportedly been dating for several months.

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