Red Sox 6, Athletics 3: Jonny Gomes clubbed Boston’s second grand slam in as many games and Jon Lester struck out a career-high 15 to turn away visiting Oakland.

Lester (3-4) dominated through eight innings while allowing one hit and two walks to avoid a third straight loss before the bullpen cleaned up its own mess in the ninth to close it out. David Ortiz and David Ross each added a solo home run for the Red Sox, who took Friday’s series opener behind Dustin Pedroia’s grand slam.

Tommy Milone (0-3) started for the Athletics and loaded the bases on a single and two walks in the first inning before Gomes came up with one out and slammed a first-pitch fastball into the seats above the left-field wall for a quick 4-0 lead. Milone ended up going four innings and was charged with six runs on as many hits and four walks while striking out five.

Ortiz led off the third and blasted an 0-2 changeup over the bullpens in right-center for his sixth home run and a 5-0 gap. Ross got a changeup over the middle in the fourth and lined it into the seats above the “Green Monster” to extend the lead to 6-0.

Lester struck out two in each of the first two innings before Craig Gentry singled leading off the third for Oakland’s lone hit off the left-hander, who struck out the side in the eighth to end his afternoon. Chris Capuano came on in the ninth and surrendered hits to the first three batters he faced before hitting Josh Donaldson and turning it over to Koji Uehara, who walked Yoenis Cespedes to load the bases and allowed an inherited runner to score on an error but eventually locked up his seventh save.

GAME NOTEBOOK: Lester eclipsed his previous career high of 13 strikeouts at Seattle on July 24, 2010. … Ortiz’s home run was his 379th as a member of the Red Sox, tying him with Dwight Evans for fourth on the team’s all-time list. … Oakland has managed four runs in two games at Boston after putting up 25 in a three-game sweep of the Texas Rangers earlier in the week.