Gonzalez boosted his major league-leading RBI total to 67 since the Padres, unable to give him a lucrative contract, traded him to the Red Sox in the offseason for three top prospects. He went 3 for 5 to increase his batting average to .353, also the best in the majors.
Tied at 3 going into the seventh, Gonzalez drove in the go-ahead run with a one-out double. After Kevin Youkilis flied out, the Red Sox scored nine more runs.
Boston entered with baseball's best batting average at .275 and scored at least 10 runs for the fifth time in nine games. San Diego, which began the day with a major league-low .232 average, has lost a season-high six straight games.
Matt Albers (2-3) pitched 1 1/3 scoreless innings to get the decision as the AL East-leading Red Sox won for the 14th time in 16 games to remain 1 1/2 ahead of the New York Yankees.
Boston scored single runs in the first, third and fourth off Wade LeBlanc. San Diego tied it in the sixth on a three-run homer by Orlando Hudson off Andrew Miller, making his first appearance of the season after being called up on Sunday from Triple-A Pawtucket.
Cory Luebke (1-2) had struck out six of his nine batters heading into the seventh. He started that inning by walking Jacoby Ellsbury. Dustin Pedroia then hit a bouncer to second baseman Hudson but hustled down the line to narrowly avoid a double play. Gonzalez followed with his tiebreaking single.
After Youkilis was retired for the second out, David Ortiz was walked intentionally and J.D. Drew walked, loading the bases. Ernesto Frieri then hit the next two batters — Marco Scutaro and Jason Varitek — to make it 6-3. Josh Reddick tacked on a two-run single, and Pedroia walked with the bases loaded. Gonzalez drove in two more with a base hit and Youkilis had a two-run double.
It was the most runs for the Red Sox in a single inning since they scored 12 in the sixth in a 13-3 win over Cleveland on May 7, 2009. The team record is 17 runs in the seventh against Detroit on June 18, 1953.
The previous biggest inning for the Red Sox this season was seven runs in three games, the last on June 11 at Toronto.
Boston added another run, on a bases-loaded walk to Ellsbury, in the eighth.
Notes
Chase Headley went 4-for-5 for the Padres. … Ortiz has hit in 14 straight games at Fenway Park. … Padres manager Bud Black made his major league debut at Fenway on Sept. 5, 1981, for the Seattle Mariners. He faced one batter, Rick Miller, throwing a wild pitch before allowing a single. … Boston manager Terry Francona is considering using first baseman Gonzalez in the outfield for some games during a nine-game interleague trip to Pittsburgh, Philadelphia and Houston. That would give designated hitter Ortiz a chance to play first base rather than miss all the games. Gonzalez has played the outfield just once in his 929 games — making three putouts and an error on Sept. 30, 2005, for the Texas Rangers against the Los Angeles Angels. … Padres catcher Nick Hundley broke an 0-for-17 slump with a single in the eighth.