New York won at home over Boston as Don Mattingly broke a 2-2 tie in the seventh with a two-run double.
Boston's Tim Lollar (5-7) took a 2-2 tie into the seventh, but threw ball four to Butch Wynegar into the dirt.
When catcher Rich Gedman retrieved the ball, he tried to catch Wynegar turning the wrong way at first. He threw high, off Bill Buckner's glove, allowing Wynegar to take second.
Bobby Meacham popped up trying to sacrifice, but, when Buckner dove for the ball and missed it, Meacham got a single and Wynegar held second. One out later, Mattingly came up, hitless. He drove an outside pitch down the first base line.
"I didn't hit the ball that well," he said, "When I hit it, I thought it was right at Buckner."
But Buckner was playing well off the line and the ball went over the bag for a double; Mattingly had his 97th and 98th RBI, and had hit in his 16th straight game.
"We pitched him away and we played him away," Boston Manager John McNamara said, "and he hits the pitch the other way anyway. That's why the Yankees are a hot ball club."
The Red Sox had tied it 2-2 in the top of the seventh, denying Phil Niekro his 296th victory. Niekro walked Jim Rice, who had homered in the second inning, and Gedman to start the inning. One out later, Steve Lyons singled to load the bases and finish Niekro.
New York's left fielder, Billy Sample, kept the game from getting out of hand. When Barrett hit a fly to shallow left off reliever Rich Bordi, Sample dove and caught it. Rice couldn't score because he had broken for home prematurely, then had to tag up.
Bob Shirley relieved and yielded Wade Boggs' single to left that scored Rice, but Sample threw out Gedman at the plate to end the inning.
Highly touted but delicate-armed Roger Clemens was to have started for Boston but said his shoulder felt tight when he warmed up.