And a Red Sox-Astros AL Division Series presented by Doosan is also now set, as Houston's loss allowed the Indians to clinch the league's No. 1 seed. Boston and Houston will play one more tune-up in Sunday's Game No. 162 before reconvening on Thursday at Minute Maid Park for Game 1 of their best-of-five series.
It had been a trying few days for the Sox, who opened their homestand on Monday with a five-game lead in the division only to have it shrink to two after Friday's defeat. But the Red Sox were able to pull through on Saturday, winning consecutive AL East titles for the first time in team history.
"It feels great," said closer Craig Kimbrel, who struck out George Springer to end it and set off the on-field celebration. "It's been a long, tough season. We have a long way to go. We have a lot to celebrate."
The Astros and Red Sox have split their six meetings this season, with Houston outscoring Boston, 31-19. This will be their first postseason meeting.
"This was the most probable outcome just the way the weekend was lining up. It doesn't surprise me," Astros manager A.J. Hinch said. "The first three games here were played with a little concern about that being a potential matchup. We were just playing, trying to win. Obviously, I don't know how tomorrow is going to go for either team. It's fun. This is a good team across the way, we're a good team, we're both division champions. We'll obviously see a lot of each other over the next 10 days."
Fittingly, the clinching game had some trying moments, particularly when the dangerous Springer stepped to the plate as the potential go-ahead run in the top of the seventh with the bases loaded and two outs. But David Price, who has been marvelous for the Red Sox since moving into the bullpen, struck out Springer on three pitches, drawing roars from the Fenway faithful.
"To me, David was throwing a lot of quality strikes," said Red Sox manager John Farrell. "That was a critical inning at a critical juncture of the ballgame. I couldn't be more proud of this group and the way they were able to go out and do it on their own terms."
After Price's escape, Mookie Betts belted a solo homer over the Green Monster to give Boston some insurance.
Addison Reed took care of the eighth, and Kimbrel closed it out in the ninth, giving the 93-68 Red Sox their ninth division title since the inception of the AL East in 1969. After taking over sole possession of first place on Aug. 1, Boston never gave it back, despite a hard charge from the Yankees.
"This is real good, real good," said Red Sox shortstop Xander Bogaerts. "It took us 161 games to win the division. That's the main goal in Spring Training. You start off with that and then the World Series. This is probably one of the most emotional ones. One-hundred and sixty-one games, that took a long time."
Drew Pomeranz gave the Red Sox exactly what they needed and had lacked in recent days -- a shutdown performance from a starting pitcher. The lefty was sharp from the outset, holding the Astros to three hits and a run over six-plus innings while improving to 17-6 to finish off the best regular season of his career. It was a nice bounceback for Pomeranz after he lasted a season-low two innings last time out against Toronto.
All Pomeranz needed was a little offense, and Boston gave him some in the mid innings. Hanley Ramirez (RBI single) and Rafael Devers (RBI double off the Green Monster) made it 2-0 in the fourth.
Bogaerts, who made a sweet play in the hole and got a force at second in the top of the fifth, jump-started the three-run rally in the bottom of the inning with a one-out double. Andrew Benintendi drove him home with a single. Mitch Moreland's two-run double spread out the game at 5-0.
"This year has included everyone," said Pomeranz. "It is a great feeling when the whole group of guys help in doing the work."
MOMENTS THAT MATTERED Helped by deflection, Price escapes: The Astros opened the seventh with four straight hits to slice Boston's lead to 5-2, and Farrell brought Price on with runners on first and second. Brian McCann hit a 95.5-mph grounder that Moreland tried to stop, but it deflected off his glove. But the Red Sox caught a break, as Brock Holt caught the deflection, and Price alertly covered first in time to record the big out. Price got out of the inning with no further damage and finished Springer off looking on his hardest pitch of the day -- a 95.2-mph two-seamer.
Double steal, Moreland double pads lead: A double steal by Benintendi and Betts in the bottom the fifth not only eliminated the possibility of an inning-ending double play, but set up Moreland for the two-run double to the gap in left-center that made it 5-0, Red Sox. Moreland came through with his big hit against lefty specialist Tony Sipp. Though September wasn't Moreland's best month, he was opportunistic, driving in 16 runs while getting just 18 hits.
"Man, it was as good as you could get. You're talking about probably the most important game of the season for us and he went out there against one of the best lineups in the league and just dominated. He was every bit of what we needed." -- Red Sox ace Chris Sale, on Pomeranz
SOUND SMART WITH YOUR FRIENDS
• Farrell became the first manager in Red Sox history to win three division titles.
• The Red Sox are 70-8 when they score five runs or more.
• Betts joined Colorado's Nolan Arenado as the only players to have 100 runs and RBIs in the last two seasons.
Red Sox catcher Christian Vazquez nabbed Cameron Maybin trying to steal second base to end the fifth inning, but Hinch challenged the call. After a brief review, the call on the field stood.
WHAT'S NEXT Astros: Right-hander Collin McHugh will start Sunday's 2:05 p.m. CT regular-season finale at Fenway Park. McHugh (4-2, 3.45 ERA) has done solid work after missing the first 3 1/2 months of the season with an arm injury. In his past six starts, he's 4-0 with a 2.12 ERA and 29 hits allowed in 29 2/3 innings.
Red Sox: With the division title clinched, the Red Sox scratched Sale from his scheduled start on Sunday and Hector Velazquez will get the nod instead. First pitch of the regular-season finale is set for 3:05 p.m. ET.