An incident following the opening day baseball game between the Los Angeles Dodgers and San Francisco Giants should make all fans reflect on the fanaticism surrounding sports on all levels, from sandot to professional.

At Dodger Stadium, after Thursday’s 2-1 Dodger victory, two men wearing Dodgers clothing severely beat a Giants fan, leaving him in critical condition, as thousands of people walked out of the stadium.

People shouldn’t have to be reminded that sports are competition — but the result is never a ticket for violence.

The same kind of nonsensical mind-set is in play following many championship games — especially following pro championship contests — where some fans display their joy by overturning cars, breaking businesses’ windows and starting fires.

It’s gotten to the point where many people living in pro-team cities — and the officials of those communities — dread a championship because of the mob violence that a big victory might trigger.

That situation is mimicked on some college campuses following a sports championship, where students take to the streets in an unruly manner to “celebrate.”

But perhaps the seed for what occurs today on the sports victory front is planted at the sandlot level. It is there that parents often lose control — cursing umpires or other officials, arguing with parents of the opposing team, criticizing team managers for not allowing their child to play in a game. In other cases they make disrespectful references to opposing players, setting terrible examples for their children about appropriate behavior at sporting events.

It would be better if some parents never attended their children’s games, rather than providing a negative influence about sports and civility.

The negativity surrounding sports is worse than it ever has been. And, the Dodgers fans who attacked the Giants fan got the 2011 baseball season off on the wrong foot.

It’s important for fans to remember that, whether their team wins or loses, they probably will reap no personal financial or other benefits. The players on the winning team get a bigger paycheck than the losers — besides their regular paychecks in which players, win or lose, make much more for one game than most people make while working for an entire year, maybe several.

The city of Pittsburgh wasn’t cast into ruins when the Steelers lost to the Green Bay Packers in the Super Bowl in February. Sights are now focused on the 2011 season, if the current labor dispute is resolved in time.

The pro hockey and basketball championships will be decided over the next couple of months, but the victories in those professional sports shouldn’t require the championship cities to prepare as they would for predictions of a natural disaster.

Sports can be great but sports, at all levels, also can be ugly.

Thursday at Dodger Stadium was an abhorrent example of the worst of sports culture.