The movie “Big Fan” wastes very little time setting up the tone of the movie. The first scene is a still shot of a parking ramp ticket booth with barely audible dialogue from sports radio. Paul, the man inside, spends hours each day drafting scripts for his call-ins to sports radio.

In the real world, Paul (Patton Oswalt, “The Informant!”) lives with his mother, masturbates chronically and doesn’t even have the money necessary to attend the New York Giants games his life revolves around. Instead he sits outside with his only friend Sal (Kevin Corrigan, “Pineapple Express”), cheering in the sincere belief his presence as the Giants’ “No. 1 fan” is a key element to their success. On sports radio, though, “Paul of Staten Island” is a force of nature, beloved for his passion and acerbic comebacks to his rival “Phil of Philadelphia.”

“Big Fan” is the directorial debut of Robert Siegel, who previously wrote the screenplay for “The Wrestler.” Traces of a first time director are apparent throughout the movie — even during its brief running time, “Big Fan” contains several moments that seem stretched out beyond reason.

For example, there is a particularly frustrating scene in which Siegel slowly builds up Paul’s harrowing journey to Philadelphia only to cut inexplicably away. The pacing is excellent, but Siegel is unable to execute much of the tension he creates. However, as a director Siegel demonstrates an excellent idea for detail. In one early scene he focuses the camera between a birthday cake and the enormous fake breasts of Paul’s brother’s wife. In one shot Siegel manages to juxtapose the superficiality of the brother’s success with Paul’s limited idea of sports radio success.

Like “The Wrester,” “Big Fan” is an intensely focused character piece about a man caught up in his fantasy life being suddenly and relentlessly beaten down by reality. In “Big Fan,” this occurs when Paul and Sal follow Giants quarterback Quantrell Bishop (newcomer Jonathan Hamm) from a gas station to a gentleman’s club. At first, the QB is amused by his presence, but when they explain that they followed him he launches into a blind rage and Paul wakes up three days later in the hospital.

The remainder of the movie charts Paul as he slowly self-destructs. We realize Paul could never destroy Bishop because his meaning as a person is contingent upon the success of the New York Giants.

“Big Fan” spares no pity for Paul — each scene maintains an air of detachment about it as we watch Paul fall further away from reality. In one of the movie’s most telling moments, Paul’s mother invades one of his phone calls and criticizes Paul for being unhappy because he doesn’t have a wife, doesn’t have friends or a house and “is married to his right hand.” Paul throws a tantrum in response and tells her that he “doesn’t want what they got.”

What’s most striking about Paul’s sentiments is his sincerity. Paul is willing to go so far as to repeatedly dismiss police investigations and lose the support of his family to preserve his perceived inclusion in his favorite sports team. Paul’s family doesn’t understand he is lost to traditional conceptions of happiness. After waking up in a hospital, Paul asks first how long he has been hospitalized and second how the Giants are doing.

Oswalt, best known as a stand-up comedian, is primarily responsible for Paul’s believability as a character. While it would be easy to perceive Paul as frustratingly stupid, Oswalt plays Paul as a man immersed completely in his individual pursuit of happiness. To Paul, it is his family that fails to grasp the importance of his role as a fan.

Perhaps the movie’s greatest trick is that as Paul slides slower into destruction he also becomes more and more empathetic. Every other character in the movie is more successful than Paul, but none of them seem as happy. In one scene, Paul successfully manages to drop the case against Bishop. We would think anyone should be furious that they were responsible for the freedom of the man who assaulted them, but Paul looks secretly about the bar, barely able to suppress a smile.

There is no doubt that Paul is pathetic to any viewer, but in his world he is a hero. By portraying the full force of his character “Big Fan” asks us if happiness by our own standards is wrong, even if nobody else understands what that means.

4 stars out of 5.