Rigged (2008) on Netflix

Michael Dublin is a full-time con man working the underground boxing circuit. A lonely drifter on the run from a past best forgotten, he moves from one scam to another, leaving a trail of enemies in his wake. Dublin invents his best scam yet when he meets Katherine Paker, a female fighter with the skills to take down a man twice her size. In a scheme Dublin calls "fight-rigging, in reverse", the two hit the road working fights in seedy basement bars, abandoned warehouses, and backwoods county fairs. But Dublin's shady past catches up with them and suddenly the stakes are higher - and more dangerous - than they'd ever imagined.