BOSTON -- When talking about the Tampa Bay Rays, it's easy to forget the team still has elite starting pitching. So much of the discourse around the Rays has centered around their use of the opener, a bullpen day they have integrated this season every fifth day as a regular part of the rotation. All of this was born out of desperation and necessity in 2018 and helped the perennial American League East underdog Rays win 90 games in a season in which few expected them to finish above .500.

But as Tyler Glasnow reminded the Boston Red Sox on Sunday, Tampa Bay's starting pitching is more than just a bunch of relievers rolling out every couple of days. As the Rays finished off a rain-shortened, two-game sweep of their division rivals with a 5-2 victory Sunday, the team's actual starting pitchers proved once again that they're more than just anomalous oddities. They're the foundation for the best team in baseball through the first month of the season, a team that will be able to match stride for stride with the Red Sox and Yankees for the rest of the season if their starting pitching is as good as it has looked. Editor's Picks Dear MLB teams: Don't trade with the Rays, you won't win

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"Ever since we acquired [Glasnow], you've seen continual progress. Even last year, we saw a lot of progress, and this year, he's just taken off," said manager Kevin Cash. "He's pretty special when he's out on the mound. Really good hitters have difficult at-bats against him."

Between Glasnow, sinkerballer Charlie Morton and reigning Cy Young winner Blake Snell, the Rays look more like a team built around top-level starting pitchers than anything else. So far this season, the Tampa Bay trio has combined for a 2.32 ERA in 93 innings pitched. Glasnow rolled through the Red Sox with ease on Sunday, tossing 6 ⅔ innings, allowing two runs, striking out nine and walking one. Despite finding himself in the middle of the best stretch of his MLB career so far -- posting a 1.75 ERA with 38 strikeouts and seven walks in six starts this season -- Glasnow isn't spending much time thinking about the numbers.

"It's much better than the previous year, so it's a positive for sure," Glasnow said. "The work I put in the offseason and the changes I made in my mentality are really starting to pay off."

Red Sox ace Chris Sale did not pitch poorly against The Rays, allowing two earned runs in seven innings pitched, striking out eight, walking three and allowing four hits, including a homer. After struggling through his first inning, allowing two runs, the Red Sox defense fell short. Rafael Devers bobbled a potential inning-ending double play, which eventually led to a Yandy Diaz double that bounced off the center-field wall after center fielder Jackie Bradley Jr. gave chase and saw the ball barely fly over his glove.

Has Rays righty Tyler Glasnow already stepped into the front rank of starting pitchers? Steven Senne/AP Photo

But for everything that didn't fall Boston's way, Glasnow was simply better. The Rays hope this early-season start for their young flamethrower isn't just a blip on the radar.

"He's totally capable of doing this," Cash said. "I don't know if it's fair for the expectation for the pitcher to go out and dominate the way that he has. We gotta allow hiccups here and there. I know when he's out on the mound and it's his day to start, we feel really good about ourselves, and that's the best way you can value a performance and what you think is going to take place."

Tampa Bay snagged Glasnow alongside rising young outfielder Austin Meadows in a trade with the Pirates last summer that sent Chris Archer to Pittsburgh. Glasnow, who's strikingly tall even for a pitcher at 6-foot-8, struggled with consistency and command after making his MLB debut in 2016 with top-100-prospect pedigree.

So far in 2019, Glasnow has made major strides with his control, posting a 0.94 WHIP this year, compared to the 1.44 WHIP career mark from his three previous seasons. The 25-year-old righty said his work with pitching coach Kyle Snyder has helped him make significant improvements this year, and that starting over in Tampa after struggling in Pittsburgh has solidified his own confidence.

"A fresh start is probably what did it," Glasnow said. "It's a really relaxed atmosphere. It's kind of that 'go out and play baseball in the backyard' mentality." Is Acuna poised to be baseball's best? One year after he put on a Braves jersey for the first time, Atlanta's talented outfielder is already placing his name among lofty company. Jeff Passan

The Rays continue to perch atop the AL East in a division containing a talented but hobbled New York Yankees squad and the defending World Series champions, in large part due to Glasnow's emergence in the early part of the season. Glasnow's success has been emblematic of Tampa Bay's roster-building strategy, which has focused on developing young talent -- who cost significantly less than signing a veteran on the open market -- and identifying undervalued talent on other teams. It's how the Rays ended up with guys in their lineup such as Tommy Pham and Yandy Diaz, both also off to strong starts this season.

It's also why the Rays looked at the Pittsburgh version of Tyler Glasnow, who had posted a 5.79 ERA in 56 games shuffling between the bullpen and rotation, and acquired him, hoping he could maximize his potential. And so far, Tampa Bay's version of Tyler Glasnow looks like a different pitcher, someone who could help carry the Rays to a postseason berth.

"The physical stuff has come along with the mental stuff," Glasnow said. "I think I've always had the ability to throw strikes. I just needed to believe my stuff. That's what's changed."