ST. PETERSBURG -- Shane McClanahan insisted the stage did not matter. Scaling the mound to face the Red Sox in a battle for first place before a national television audience and a crowd of 17,816 at Tropicana Field, the 24-year-old left-hander said, was just another opportunity to pitch.

But the Rays knew what was at stake this weekend and delivered a three-game performance worthy of the moment, taking another step toward their ultimate goal of winning the American League East by completing a sweep of the Red Sox with a 3-2 victory on Sunday night.

• Box score

The Rays have won four straight games as the Red Sox have dropped four in a row. During that stretch, Tampa Bay has turned its 2 1/2-game deficit in the AL East into a 1 1/2-game lead over Boston. Once again, the Rays are the team to beat in the division.

“It’s no secret that the Red Sox are a great team,” outfielder Manuel Margot said through interpreter Manny Navarro. “They’ve been up in the first-place area along with us pretty much all year, but I think we can hang with them and hang with any other team.”

Sunday’s series finale was, in many ways, a perfect representation of so many things the Rays do well.

McClanahan, one of the young arms they’re counting on down the stretch, put together an excellent start. The Rays played solid defense all over the field, with their infielders scooping up everything hit to them while outfielders Kevin Kiermaier and Margot made highlight-reel plays near the wall. They had a few tough at-bats and timely hits. And their bullpen, battered by injuries as it may be, came through with key outs.

“I think we came out and we played our baseball, in all honesty. It's kind of what we expect out of ourselves,” second baseman Brandon Lowe said. “We know that we're not going to win every single game, but if we can play like we did these past few days, we'll be in good shape.”

Nobody thought the stage would be too big for McClanahan. As the 24-year-old left-hander dryly reminded reporters on Saturday afternoon when asked about starting the Majors’ only Sunday night game this week, “I pitched in the World Series.” Perhaps that experience last October, when McClanahan debuted in the postseason and faced the Dodgers once in the Fall Classic, is already paying dividends this year.

“I feel like once you start letting outside distractions get in, that's when you lose focus on what you need to do,” McClanahan said. “I took the ball like it was any other game, and ultimately, that's how I approached it.”

The lefty looked calm and in control from the start and made arguably his best start of the season against Boston’s dangerous lineup. McClanahan allowed only one run on four hits and two walks while striking out seven over six innings, throwing 62 of his 88 pitches for strikes and forcing the Red Sox to swing and miss 15 times.

McClanahan’s last two innings were his most efficient. After allowing a leadoff single to Kiké Hernandez in the fifth, McClanahan got Rafael Devers to hit into a 4-6-3 double play on a first-pitch curveball, then forced J.D. Martinez to fly out to center to end a seven-pitch inning. He then retired the side in order on 10 pitches in the sixth.

“Mac was just really, really good,” Rays manager Kevin Cash said. “We needed him to step up. He did step up.”

But Red Sox right-hander Nick Pivetta got off to another excellent start, retiring the first eight hitters in order and extending his scoreless streak against the Rays to 13 2/3 innings. That run finally ended as Tampa Bay took advantage of the few mistakes he made.

With two outs in the third, Mike Zunino walked on four pitches. Up came Lowe, who got ahead in the count, 3-0, before Pivetta blew two high fastballs by him. At that point, Lowe said, his only thought was to not get beat by another fastball. But Pivetta threw a full-count slider that spun in the middle of the strike zone, and Lowe ripped his 23rd home run of the season out to right field, then flipped his bat as he stepped out of the box.

Former Ray Hunter Renfroe cut Tampa Bay’s lead in half, launching his 16th homer of the year out to center field with one out in the fourth inning. But rookie shortstop Wander Franco helped produce what turned out to be the deciding run in the fifth.

The 20-year-old top prospect ripped a single to center as part of his third straight multihit game, advanced to second on a wild pitch and scored on Margot’s single to right off Pivetta. That ensured the Rays would still have a one-run lead when Alex Verdugo doubled and scored on a wild pitch by Drew Rasmussen in the seventh.

“Manny and Wander, two big at-bats. Starting to see some things [with] Wander that's made him special,” Cash said. “Spoiling pitches and extending at-bats, that's what's made him really, really good at league-age 20, and now we're seeing that in the big leagues.”

Lefty Ryan Sherriff -- the lone southpaw in the Rays’ bullpen now that Jeffrey Springs is on the injured list -- recorded a huge out to finish the eighth inning, retiring Verdugo with the tying run on first base. Then right-hander Matt Wisler, picked up in a low-profile trade with the Giants earlier this summer and now thriving in a higher-leverage role with the Rays, worked the ninth inning to earn his third career save.

“The guys put it together and played really, really good baseball,” Cash said. “They're a good team. We're a good team. And fortunately for us, we played really, really well to be able to win three. That's not easy to do.”