SANTA MONICA, Calif. (AP) _ O.J. Simpson took the witness stand at last today, swearing he ``never'' hit, struck or slapped his ex-wife and saying she lied by writing in journals that he had.

Plaintiff attorney Daniel Petrocelli, who called Simpson as a hostile witness in the wrongful death lawsuit, began by grilling the former football star about his stormy relationship with Nicole Brown Simpson.

Simpson, beginning what was expected to be three full days on the stand, at times sounded testy and annoyed as Petrocelli asked the same questions over and over in slightly different ways.

Asked how many times he had ``hit,'' ``struck,'' or ``slapped'' his ex-wife, Simpson repeatedly answered ``Never.''

The lawyer asked whether Ms. Simpson had lied when she wrote in journals and told others that Simpson had hit her.

``Yes,'' Simpson said.

The attorney then read from Simpson's deposition: ``It's as if she can't stand when things are quiet and has to shake things up.''

Petrocelli asked Simpson if the couple ``knew how to push each other's buttons.''

``Yes,'' Simpson replied.

Simpson admitted the couple had a ``physical altercation,'' saying, ``Once I grabbed her and pushed her out the door.'' But he said his wife had struck him numerous times.

Petrocelli worked to establish that Simpson had struck his wife in the face and choked her intentionally during the fight.

Looking at photos of Ms. Simpson taken later, Simpson said some of the marks on her face would have been caused by her habit of picking at her facial blemishes.

``A lot of this redness would be there normally after she picked and cleaned her face,'' Simpson said.

But asked specifically if he knew if she had caused any of the injuries or the marks in the photo, Simpson replied, ``I don't know.''

He said he could not remember what specifically caused a split lip, a welt over her eye and what appeared to be choke marks on her neck.

``I rassled her out of the room. What happened when she fell, I don't know, but I feel responsible for all of it,'' Simpson said.

Again and again, Petrocelli pressed him for specifics, asking of the injury over her eye: ``Did you hit her there?''

``No,'' Simpson said.

Simpson arrived at the courthouse wearing a gray suit, slipping by a crowd of hundreds outside the courthouse to shouts of ``Murderer! Murderer!'' The other principals in the case arrived to equally colorful receptions.

Simpson's attorney Robert Baker smiled when he was booed.

Attorney James Q. Kelly escorted Nicole's mother, Juditha, and sister Denise Brown in to chants of ``We're behind you, Denise!'' ``God bless you!'' and ``Go get him!''

A group of white women who support Simpson started yelling, ``O.J. is innocent! O.J. is innocent!'' but another faction yelled back, ``Guilty! Guilty! Guilty!''

When Petrocelli arrived with the family of Ronald Goldman, there was applause and screams of ``White justice!''

Sixteen people, and five alternates, were chosen from the crowd to be in the room for Simpson's testimony.

The crowd started arriving at 4 a.m. About 200 stubs were placed in a glass bowl and at 7:15 a.m., a court employee and sheriff's deputy pulled out the winning numbers as members of the crowd yelled, ``Come on, baby!'' and ``Please, please, please.''

The first number called belonged to Avis Davis, a 75-year-old retiree who walks five miles a day to get to the courthouse. She said she was ``ecstatic, tickled to death. How could you not be? You have to be curious about what he has to say and how he will justify what happened,'' she said.

Simpson never testified at his criminal trial, explaining later he feared the sequestered jury was growing too weary. Also, he was spared incriminating himself and jeopardizing what proved to be a winning defense.

Both sides have made it clear that Simpson's testimony is key, perhaps pivotal, to the outcome. His statements, demeanor, consistency and credibility all will be scrutinized.

One bad slip and he could be out of millions of dollars and what remains of his reputation. But with a sensational performance, and he could be on the road to final vindication.

Underscoring the importance is the way the trial has gone for Simpson so far. Judge Hiroshi Fujisaki has barred testimony by perjured ex-policeman Mark Fuhrman and warned the defense about raising unproven theories of conspiracies or planted evidence.

And new evidence not introduced at the criminal trial has been troublesome _ including a photograph from a 1993 football game showing Simpson wearing the kind of Bruno Magli shoes that left bloody footprints at the crime scene.

Today's testimony marked a crowning moment in the case, which has seen everything from a silly and surreal freeway chase to stunning not-guilty verdicts that divided the nation along racial lines.

Simpson was arrested June 17, 1994, after that chase and charged with murder. He spent 474 days in jail during the long, tumultuous trial before his acquittal last October.

Despite the acquittals, the families of the victims filed wrongful death lawsuits, claiming he was responsible for the slayings and should be made to pay.