The Fighter

On the night of an undercard fight in Atlantic City, Micky's scheduled opponent is ill, and a substitute is found who is 20 pounds heavier than Micky, a huge difference in professional boxing, constituting two or three weight classes. Despite Micky's reservations, his mother and brother agree so that they can all get the purse and Micky is defeated. Micky retreats from the world and forms a relationship with Charlene Fleming, a former college athlete who dropped out and became a bartender.
After several weeks, Alice arranges another fight for Micky, concerned it will turn out the same. His mother and seven sisters blame Charlene for his lack of motivation. Micky mentions he received an offer to be paid to train in Las Vegas, but Dicky says he will match the offer so he can keep training and working with his family. Dicky then tries to get money by posing his girlfriend as a prostitute and then, once she picks up a client, impersonating a police officer to steal the client's money. This is foiled by the actual police and Dicky is arrested after a chase and a fight with them. Micky tries to stop the police from beating his brother and a police officer brutally breaks his hand before arresting him. At their arraignment, Micky is released, but Dicky is sent to jail. Micky washes his hands of Dicky.
On the night of the HBO documentary's airing, Dicky's family, and Dicky himself in prison, are horrified to see it is called Crack in America how crack addiction ruined Dicky's career and life. Dicky begins training and trying to get his life together in prison. Micky is lured back into boxing by his father, who believes Alice and his stepson Dicky are bad influences. The other members of his training team and a new manager, Sal Lanano, persuade Micky to return to boxing with the explicit understanding that his mother and brother will no longer be involved. They place Micky in minor fights to help him regain his confidence. He is then offered another major fight against an undefeated up-and-coming boxer. During a prison visit, Dicky advises Micky on how best to work his opponent, but Micky feels his brother is being selfish and trying to restart his own failed career. During the actual match, Micky is nearly overwhelmed, but then implements his brother's advice and triumphs; he earns the title shot for which his opponent was being groomed.
Upon his release from prison, Dicky and his mother go to see Micky train. Assuming things are as they were, Dicky prepares to spar with his brother, but Micky informs him that he's no longer allowed per Micky's agreement with his current team. In the ensuing argument, in which Micky chastises both factions of his family, Charlene and his trainer leave in disgust. Micky and Dicky spar until Micky knocks Dicky down. Dicky storms off, presumably to get high again, and Alice chides Micky, only to be sobered when he tells her that she has always favored Dicky. Dicky returns to his crack house, where he says goodbye to his friends and heads to Charlene's apartment. He tells her that Micky needs both of them and they need to work together. After bringing everyone back together, the group goes to London for the title fight. Micky scores another upset victory and the welterweight title. The film jumps a few years ahead, with Dicky crediting his brother as the creator of his own success.

Question: Where is the undercard fight?
Answer: Atlantic City; Atlantic City