BOSTON -- One swing by Big Papi brought relief to many at Fenway Park.
"I'm sure he's going to feel good about it," Boston manager Terry Francona said. "Obviously we do."
The Red Sox won for the sixth time in seven games.
Ortiz entered the game hitting just .111, the lowest of any regular in the majors. His slam was his seventh with the Red Sox, and seventh at Fenway -- tying a record held by Ted Williams and Jim Rice.
Ortiz's slam -- his first hit at Fenway this season -- erased Boston's 1-0 deficit against starter Luis Mendoza (0-1) in the third after Jed Lowrie doubled and Jacoby Ellsbury and Pedroia walked. It was his second homer of the season.
"It's just a matter of time," Red Sox catcher Jason Varitek said. "It was a big lift for him."
The third started easily for Mendoza, who retired the first eight batters of the game. Varitek popped weakly to third and Sean Casey lined to short. Lowrie then doubled into the left-field corner.
Following the walks, Ortiz -- hitting just .109 when he came up -- walked slowly to the plate. The crowd, seemingly trying to help get the slugger on track, gave him a standing ovation. On the first pitch, he lofted a fly ball into the Green Monster seats' first row, and was serenaded with chants of "Papi, Papi" when he reached the dugout.
"He creates lift in a crowd regardless of whether he has a hit or not," Varitek said. "He's Big Papi for a reason."
When Ortiz reached the dugout, his teammates gave him the "silent treatment" before mobbing him.
"Even though the big boy is struggling, he's still dangerous," Texas manager Ron Washington said.
Ortiz left the clubhouse before speaking to reporters after the game, but said on the club's flagship radio station postgame show: "My teammates are the best. They are so happy to see me come through."
Matsuzaka (4-0) gave up three runs and five hits with two walks and four strikeouts in 5 1/3 innings. He labored through the first three, throwing 62 pitches, but held the Rangers to one run and two hits.
The Red Sox chased Mendoza and scored five more in the fourth. Vartiek had an RBI double and scored on Lowrie's sacrifice fly. Ellsbury tripled home a run and Pedroia homered over the Monster.
"(I) try to stay ahead first pitch," Mendoza said of his fastball to Ortiz. "With the two walks, I started down. I just left the ball in the middle."
Mendoza was tagged for seven runs on five hits in three-plus innings.
Blalock homered into Boston's bullpen in the sixth.
Josh Hamilton's sacrifice fly gave Texas a 1-0 lead in the third.
- Ortiz was 0-for-18 at Fenway before the homer.
- Ortiz had one slam at Fenway with Minnesota.
- Texas LHP Kason Gabbard and OF David Murphy, each traded from the Red Sox last season at the deadline for reliever Eric Gagne, received their World Series rings Friday.
- The Rangers' staff had allowed only nine homers coming in, the AL's second fewest.
- J.D. Drew reached base for the 13th time in 14 games.
- The Red Sox opened a stretch of 13 of their next 16 at home.