"I was playing that ball to come back to me a little bit," Williamson said. "I called off Denard [Span]. I thought I was going to be right under it and it kind of darted the other way. I tried to recover and didn't make the play."
That brought the Red Sox faithful to their feet. The Giants fans quickly followed.
"We caught a break there, man in scoring position to lead off," Red Sox manager John Farrell said. "I felt like we had a good matchup there with Jackie."
There was no way Farrell was going to ask Jackie Bradley Jr., a .321 hitter, to bunt. He struck out looking.
"Casilla made some pitches and got the calls," said Farrell, who thought the last two pitches were a tad outside. Bradley had a short discussion with home-plate umpire Tim Timmons that led nowhere.
Chris Young, who had already homered and was swinging a hot bat, was due up. Farrell went with David Ortiz as a pinch-hitter, knowing Giants manager Bruce Bochy would call on lefty Javier Lopez, Ortiz's former teammate.
"He's the best hitter on the team," Young said. "He has to get an at-bat there."
Said Farrell: "I liked David vs. Lopez better than the other matchup."
Lopez walked Ortiz on a full count, and Rusney Castillo was sent to run for him.
"He draws a big walk there and it's a situation there we have two shots at it," Farrell said. "They made the pitches to get out of it."
Travis Shaw, who entered the game as a pinch-hitter in the seventh, struck out after sharply fouling off a pitch to the right side.
Bochy then went to righty Hunter Strickland, and Farrell countered with lefty-hitting Marco Hernandez, who drilled a one-hopper on the first pitch to Giants shortstop Brandon Crawford for the final out.
"It was a good baseball game," Boston starter David Price said. "We had the big hits yesterday and they had the big hits today."