SAN DIEGO — A man on trial for throwing a fatal punch at a professional surfer who was raised on Kaua'i acted in self-defense and should not be convicted of murder, the man's defense attorney said Monday during opening statements.

Seth Cravens, 22, is among five men accused of confronting Emery Kauanui in May 2007 and picking a fight that ended in Kauanui being punched and hitting his head on the pavement.

Defense attorney Mary Ellen Attridge said Kauanui's death "was a tragedy ... but it was not a murder." She said Cravens attacked when Kauanui got "5 inches away" in a threatening manner.

Deputy District Attorney Sophia Roach said Cravens and four other men wanted revenge for a previous confrontation with Kauanui at a bar. She said Cravens punched the 24-year-old, who hit his head on the concrete and died four days later of brain swelling.

"It made a sound that nobody has forgotten," Roach told the jury.

After Kauanui's death, La Jolla residents who claimed they were victimized by Cravens called police to report various violent incidents, from bar fights to rowdy behavior at parties and on the beach, Roach told the jury.

The prosecutor urged jurors to convict the defendant of 10 other counts, including assault, battery and making a criminal threat, in addition to second-degree murder.

Later on Monday, Kauanui's girlfriend wiped away tears as she testified about watching him fall from the punch.

"I heard his skull crack when it hit the pavement," Jenny Grosso testified in San Diego Superior Court.

"It sounded like something just pinged off the sidewalk, and then immediately there was a pool of blood coming from the back of his head. I thought he was dead right there."

Attridge said Cravens, Kauanui and the rest of men had been arguing about who was more local to the area. She said Cravens punched Kauanui with his left hand, even though he is right-handed, and after Kauanui hit his head, Cravens checked his pulse before everyone scattered.

She said the punch, in combination with the drugs and alcohol consumed by Kauanui, caused him to lose consciousness and hit his head. His blood-alcohol level was later measured at .17 percent — more than twice the legal limit — and he had smoked marijuana that night, she said.

Witnesses testified that Kauanui and the others were at a La Jolla bar when Kauanui spilled a drink on one of Cravens' friends, starting an argument. Cravens and his friends later went to the home of Kauanui's mother.

Cravens' four co-defendants pleaded guilty in June to lesser crimes. Two of them — Henri Hendricks and Matthew Yanke — will be called to testify in Cravens' defense, Attridge said outside the courtroom.

Four counts against Cravens were investigated by police but could not be prosecuted, his attorney said, arguing that the case against Cravens went from a prosecution to "runaway train" as word of Kauanui's death spread.

Cravens faces 15 years to life in prison if convicted of murder.