With his team in a one-run hole, Upton hit a two-run homer to right field off Red Sox starter Daisuke Matsuzaka in the sixth inning. It was the center fielder's 18th homer of the season to give his club a lead it wouldn't relinquish.
"You just have to go up there looking for something to hit off him," Upton said. "He just left a pitch up. ... He left a fastball up. I had a good look it. I just wanted to make solid contact."
Rays manager Joe Maddon beamed talking about Upton.
"I really believe this about him," Maddon said. "As he gains more experience, you're going to see more of that from him in the future.
"Young hitters who hit opposite-field home runs have always been an attractive thing to me. ... That home run did sound different. It jumped to right-center."
Matsuzaka lost to the Rays for the third time this season, earning the dubious distinction of being the eighth pitcher in Rays history to lose three games in a season to the Rays.
"I feel frustrated about my own pitching," Matsuzaka said. "Tonight, I wasted a lot of pitches and I feel I got myself into trouble. ... The problem is, I haven't been able to go as deep into games as I would like. ... My hope was to be able to pitch as usual and keep my pitch count down."
Meanwhile, Jackson made his 24th start of the season for the Rays and put forth yet another quality start, showing electric stuff as well as competitiveness. The Rays right-hander allowed one run on five hits and five walks in six innings and worked out of two jams.
Jackson hit Dustin Pedroia to start the third. Kevin Youkilis followed with a double before David Ortiz walked to load the bases. Jackson fell behind 3-0 to Mike Lowell before the Red Sox third baseman hit a sacrifice fly to left field to score Pedroia. Jackson minimized further damage by retiring J.D. Drew on a weak pop out to second and Jason Varitek on a groundout to end the inning.
"Definitely, I felt like that was the key inning," Jackson said. "That was the inning -- most of the year the one inning kills me -- that was definitely it. I came out of it with only one run given up. It definitely felt good. After that I told myself all right you get out of that with this team and this lineup, you definitely have to keep battling to keep your team in the game."
Upton helped Jackson escape his other jam when he cleanly fielded Lowell's fifth-inning single to center before throwing out Ortiz trying to score from second base.
"Defense stepped it up and had a lot of nice plays behind me," Jackson said.
Jackson won for the third time in his last seven starts after earning just one win in his first 17 starts with the Rays. He has pitched to a 1.36 ERA over his last five starts, allowing two runs or fewer each outing while lowering his ERA over a run and a half over the five-game span.
Upton could see a difference in Jackson.
"He definitely pitched out of some jams that earlier in the year he wouldn't have," Upton said.
Dan Wheeler took over for Jackson in the seventh and put up a scoreless frame. Gary Glover added a scoreless eighth leading to closer Al Reyes, who pitched a scoreless ninth to preserve the victory and pick up his 19th save of the season.
"They all did great," Maddon said. "Those three guys there are really the stalwarts at the end."
But the ninth didn't come easy. After Youkilis popped out to start the ninth, Reyes walked Ortiz.
"I didn't want to give him anything he could hit out," Reyes said. "He was looking to tie it up with one swing."
Lowell followed Ortiz and hit a sinking line drive to right field that Delmon Young dove for and grabbed. Not knowing whether the ball had hit before he caught it, Young didn't wait for the umpire's call and wisely threw to second base. Had the ball not been ruled a catch, Young would have had the force out at second.
"I didn't see it go in my glove," Young said. "I was caught in between. Just put your glove down and try to block it. Avoid the worst case scenario so they don't get to second and third."
Drew followed with a two-out single to bring up Varitek, who flied out to Carl Crawford in left to end the game.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.