"Good to have a rally there in that inning," Sizemore said. "We've kind of struggled with Jon on the mound. It's nice to pick him up and get some runs for him."
It wasn't all positive news for Boston in its first win this season over the rival Yankees. Closer Koji Uehara was held out of the game because he had some right shoulder stiffness when throwing during pregame warmups. Manager John Farrell used Edward Mujica in the ninth instead of the 39-year Uehara as a precaution.
"We felt it was best to stay away from him," Farrell said. "It'll be a day-to-day thing."
Jonny Gomes led off the sixth with another long ball off Sabathia, and the four-run inning was more runs than Boston had scored for Lester in his first two starts combined (one). Despite a 2.51 ERA coming in, Lester was at risk of falling to 0-3 for the first time in his big league career.
The left-hander was lifted with two outs in the seventh after Kelly Johnson singled to pull the Yankees within two runs, his first hit in 15 career at-bats against Lester (1-2). Junichi Tazawa relieved with runners at the corners and retired Derek Jeter on a flyout.
Jeter hit leadoff for the Yankees for first time since breaking his left ankle in the 2012 AL championship series opener. He beat out an infield single in four at-bats.
Lester allowed Alfonso Soriano's homer starting the second and six hits overall. He walked two and struck out six in improving to 12-5 in 27 starts against New York.
"I don't feel like I threw the ball as well the first two, but sometimes you need games like this to appreciate the ones where you glide through," Lester said. "This was a little bit of a grinder."
Tazawa pitched 1 1/3 innings of one-hit relief, and Mujica was perfect in the ninth for his first save with Boston.
"I'm ready to go whatever the situation," said Mujica, who had 37 saves for St. Louis and made the NL All-Star team last year before losing his closer's job in September.
Sabathia (1-2) pitched without the controversy that surrounded teammate Michael Pineda in a series-opening 4-1 win Thursday but also without the success. Pineda gave up one run and four hits in six-plus innings but was caught on camera with a brown substance on his hand. Joe Torre, Major League Baseball's executive vice president for baseball operations, said in a statement Friday that Pineda will not be suspended.
Looking as if he was setting aside talk of being an ace on the decline, Sabathia was dominant for five innings. He allowed just David Ross' third-inning double until Gomes led off the sixth with his first homer of the year, on an 89 mph four-seam fastball.
Four batters later, Sizemore crushed an 80 mph slider into right field for a 4-1 lead.
The duo were teammates in Cleveland before Sabathia was traded to Milwaukee during the 2008 season.
"You go out and compete, even against friends," Sabathia said. "Tonight he got the best of me."
Sabathia's fastball velocity has declined from 94.1 mph in 2009, his first season in New York, to 89.7 mph this year entering Friday. Last year he gave up 45 of his major league-leading 122 runs on a career-high 28 homers allowed. He's already yielded five this season.
Sabathia allowed four runs and six hits in seven innings, striking out nine and walking two. He's given up at least four runs in each of his three starts and has a 6.63 ERA.
"I was a little bit better," Sabathia said. "I haven't really been able to put a whole game together."
Former Red Sox Jacoby Ellsbury and Matt Thornton were given their World Series rings in a meeting with Boston GM Ben Cherington and Farrell before the game. ... Yankees manager Joe Girardi said 1B Mark Teixeira (right hamstring) should be off the disabled list before May 1 but SS Brendan Ryan (back) is doubtful for the beginning of next month. ... Red Sox OF Shane Victorino took BP and did some light running. Farrell says he'll have an idea about a rehab assignment for Victorino after the White Sox series early next week. ... Next up: Boston's John Lackey (2-0) faces New York's Hiroki Kuroda (1-1).