SALEM – The girlfriend of a Lynn man stabbed to death outside a Salem playground in April 2010 told jurors she tried desperately to stop the “waterfall of blood” coming from his chest as she drove to the police station to meet up with an ambulance.?I tried to hold his chest while trying to drive,” Jessica Fallis said through streaming tears Tuesday afternoon. “I was trying to hold the blood in.”Fallis testified on the opening day of the first-degree murder trial for Boston man Jonathan Rivera at the J. Michael Ruane Judicial Center in Salem. Rivera, 23, is accused of killing 30-year-old Shaundell Turner, of 382 Essex St., Lynn, just outside Mary Jane Lee Park in Salem on April 7, 2010. Turner died at Salem Hospital of a single stab wound to the chest.Assistant District Attorney Kristen Buxton told jurors in her opening statement that the Boston man killed Turner in a confrontation “fueled by hatred.”That argument allegedly stemmed from the fact that Rivera had had a brief relationship with Fallis in the summer of 2009 and had made disrespectful comments to her about Turner during that time.Buxton said Rivera, 23, “plunged a knife” into Turner?s chest, “causing immediate massive bleeding” that could not be stopped.But defense attorney Edward Hayden maintained in his opening statement that Rivera acted in self-defense.?The two had had problems in the past and Turner went after Rivera. Turner was winning and that?s when (Rivera) pulled his knife out,” Hayden said just before witness testimony began.About 10 people sat in the courtroom, including family members of both the victim and the accused who sat on opposite sides of the courtroom. One young girl who appeared to be a member of Turner?s family began sobbing during Fallis?s testimony, but refused to be led out of the courtroom by Turner?s mother. Instead, she muffled her sobs in the woman?s chest.Rivera had a buzz cut and wore a black dress shirt and tie. He spent much of the afternoon reading miscellaneous papers on the table in front of him or staring into his lap. He did not make eye contact with the witnesses.The first witness to take the stand following a break for lunch was a man who said he?d grown up with Rivera and saw him at the park on the day of the stabbing, but did not see the argument or the actual stabbing.Fallis testified that on the morning of April 7, she awoke to Turner making plans for a barbecue at his mother?s house. He wanted to get some food for the event at a Spanish store called Castillo?s, located on Palmer Street about two blocks past the park where the stabbing occurred. He also wanted to pick up some marijuana from a friend near the store, she said.Along the way, she said, Turner saw more people he knew in front of the park and he and Fallis stopped just before noon so he could invite them to the barbecue.At some point they were stopped at the park entrance and Rivera approached the car.?He said, ?Wassup??” Fallis said. “And (Turner) acted calmly, got out of the car.”Fallis said Turner said a couple of words to Rivera, at which time she looked away for a second because she “didn?t know what to expect.”As she looked back, she saw Rivera throwing a punch at Turner. Turner struck Rivera in turn and soon the two were fighting. Fallis said she got out of the car.?When I got to the sidewalk, I noticed (Turner) jumped back and said, ?You got a knife. Put the knife down and fight like a man,? ” Fallis testified.She said Rivera responded by swinging the knife toward Turner, who continued to back up. At some point he fell on the ground and Fallis got back in her car to make a U-turn. When she got out again, Turner had been stabbed.?I put him in the car and flew down Palmer Street toward the hospital,” she said, a tissue now held to her tear-soaked face. Fallis said she met EMTs at Salem Police headquarters just after noon and remained there to give police a statement. At 1:30 p.m. Turner was pronounced dead at Salem Hospital.Rivera fled the scene and was