BOSTON -- Travis Shaw knew he would have some sort of opportunity on Saturday.

What exactly it would be was a mystery.

The rookie infielder was called up from Triple-A Pawtucket on Friday night and learned Saturday morning that he would be starting in place of injured Pablo Sandoval at third base.

He didn't let the chance pass him by.

Shaw slugged the first two homers of his major league career and had three RBIs as the Boston Red Sox overcame another shaky start from Joe Kelly in an 11-7 win over the Tampa Bay Rays at Fenway Park.

"I tried to stick to my approach and not do too much," said Shaw, who finished with a career-high four hits and was a triple short of the cycle. "Once you get a couple of hits, your confidence level goes up and you feel good about yourself and I was able to carry through the whole game."

Shaw's first home run was a third-inning solo shot to right field and his second was a three-run blast in the eighth, putting the game out of reach as Boston (47-58) won its second straight.

"Very relaxed, confident, good swings," Red Sox manager John Farrell said. "Power to the stroke."

Shaw also scored five runs, becoming the first Red Sox player to do so since injured second baseman Dustin Pedroia scored five times against the Texas Rangers on Aug 12, 2008.

"I wasn't indifferent (about any player coming into the game), but he had a good game," Rays manager Kevin Cash said. "He got some big hits."

Shortstop Xander Bogaerts and right fielder Rusney Castillo each drove in three runs for Boston, which pounded out 16 hits.

Left fielder Hanley Ramirez and second baseman Brock Holt each had an RBI for Boston.

Kelly (3-6) gave up only one hit through three innings, but the right-hander departed after giving up five runs and nine hits and striking out six in five-plus innings for Boston.

"The first time through was pretty good," Kelly said. "The second time through they obviously scored runs and I didn't make the kind of pitches I needed to make, didn't mix it well enough. Fortunately, we had a lot of offense."

Right-handed reliever Jean Machi, making his Red Sox debut, posted the save.

Tampa Bay (51-54) didn't have starter Matt Moore for long. The left-hander surrendered six runs and nine hits in a three-inning outing.

"They swung it well today," said Moore, who dropped his third consecutive decision.

Moore has served up four or more runs in five of six starts since making his season debut on July 2 after a lengthy recovery from Tommy John surgery.

"It's not fun right now, but I still believe in myself," Moore said. "I feel like when I was out there competing that that wasn't being timid -- that was what I had and that was what I had to offer that day.

"It's tough having only three innings, handing over that many innings to the bullpen and coming out of the game. It doesn't feel good, but I think it's days like this that make the good days the great days."

Logan Forsythe hit a solo home run in the ninth and the Rays second baseman also had a two-run single in the fourth. Designated hitter John Jaso had a team-high three hits for Tampa Bay.

The Red Sox scored four runs in the second and jumped ahead 6-0 but nearly coughed up the lead as Kelly faltered.

Tampa Bay pulled to within 7-6, scoring two runs in the fourth, two in the fifth and two in the sixth.

NOTES: OF/DH Grady Sizemore, who played 52 games with the Red Sox in 2014, was recalled from Triple-A Durham and started in left field for Tampa Bay. Sizemore went 0-for-5 as his season batting average dropped to .214 (12-for-56). OF Mikie Mahtook was optioned to Durham. ... LF Hanley Ramirez went 1-for-4 with an RBI on a sacrifice fly in the cleanup spot in his return to Boston's lineup after missing Friday's game with a left shin injury. ... Red Sox 3B Pablo Sandoval (left forearm contusion) did not play and is day to day. ... Boston optioned RHP Jonathan Aro to Triple-A Pawtucket. ... INF Jemile Weeks, designated for assignment by the Red Sox on July 29, cleared waivers and was outrighted to Pawtucket. ... Rays RHP Nathan Karns (6-5, 3.37 ERA) faces Red Sox LHP Wade Miley (8-9, 4.65) in Sunday's series finale.