ST. PETERSBURG, Fla. -- Boston continues to keep its foot on the gas pedal, and starting pitching is leading the way.

Rick Porcello took a shutout into the eighth inning and the Red Sox stayed hot, winning their third straight by beating the Tampa Bay Rays 3-1 on Saturday night at Tropicana Field.

The Red Sox (85-63) got a solo home run and an RBI single from Mookie Betts, and Porcello (10-17) kept the Rays (72-77) in check the whole night.

"He led the way tonight," Red Sox manager John Farrell said. "He was economical. A lot of strikes. ... He had great tempo, attacked the strike zone. This was a big night."

Boston has won eight of its last 10 games, and the Red Sox have needed that to stay ahead of the Yankees, who have won eight of 11 but remain three games back in the American League East with 14 games to play.

The Rays got on the scoreboard in the eighth, as Adeiny Hechavarria doubled and scored on a throwing error. Kevin Kiermaier grounded out to first, but Mitch Moreland's throw to second for a potential double play hit Mallex Smith in the back and went into center field. The throwing error allowed Hechavarria to score. That put Smith at third, but Addison Reed struck out Steven Souza to end the inning.

Red Sox closer Craig Kimbrel pitched a 1-2-3 ninth for his 33rd save and his seventh straight scoreless appearance.

Tampa Bay dropped to five games under .500 -- matching a season high -- and have lost seven of their last nine. While mathematically alive, the Rays drop to six games behind Minnesota for the final American League wild card with 13 games to play and four other AL teams ahead of them behind the Twins.

Alex Cobb (11-10) lasted only 5 1/3 innings and took the loss after winning his two previous starts.

"It's as frustrating as you get," Cobb said of a second straight close home loss. "To have two tough losses like that, coming back home, it doesn't get any harder to handle."

Betts had a role in all three Boston runs. He hit a solo home run in the second, and added an RBI single in the sixth, then scoring on an RBI double by Rafael Devers.

"He's in a 10-day run here where we're seeing the guy we saw for two years leading into this year," Farrell said of Betts' solid play. "He's relaxed, he's confident. That leads to the comfortability that we're seeing."

Porcello and Cobb both pitched well early, with the Red Sox clinging to a 1-0 lead, thanks to a solo home run by Betts in the second inning. The home run -- Betts' 22nd this season -- went down the left field line and would be the only run scored in the first five innings.

Moreland followed with a double off Souza's glove in the second, but Cobb stranded him there with three straight outs, two by strikeout.

Porcello was economical in shutting the Rays out early, needing just 29 pitches in the first three innings. Kiermaier led off the game with a single, but Evan Longoria grounded into a double play to end the first. Hechavarria singled to lead off the third, but was caught trying to steal second to end that inning. Longoria doubled with two outs in the fourth and stole second, but Lucas Duda fouled out to end the fourth.

"I don't think he did anything out of the ordinary. I thought he got some generous calls on the outside of the dish," Souza said. "When he can locate a ball and he's got room to make an error, he can be pretty tough to face."

Cobb kept the Rays close, giving up another run in the sixth inning as Christian Vazquez singled and scored on a Betts RBI single. He was done after 5 1/3 innings, giving up six hits.

NOTES: Rays 1B Logan Morrison was ejected from a game he wasn't playing in, getting tossed in the sixth inning for arguing a call from the dugout. It was his first career ejection. ... Friday night's 15-inning game was, at 6 hours, 5 minutes, the longest loss in Rays' history and the third-longest game for the team. The 24 strikeouts by Rays' hitters reset a team record and is the second most in American League history -- the Angels had 26 in a 1971 game that lasted 20 innings.