In victory, the Rays (69-55) maintained the top spot in the American League Wild Card standings while remaining hot on the heels of the AL East-leading Yankees.
Though the Rays lost their season series to the Royals, 4-2, they won this week's set against their Central Division visitors to move to 15-5 in August, the best record in baseball.
Shields allowed an RBI single in the second to Jeff Francoeur and an RBI triple to Alcides Escobar in the eighth before giving way to Jake McGee, who surrendered a single to Alex Gordon that drove home Escobar. But that would be it for the Royals.
At times, Shields frustrated Royals hitters, some of whom complained about a large strike zone by home-plate umpire Scott Barry. That frustration boiled over in the eighth when Eric Hosmer struck out looking, which led to Royals manager Ned Yost getting ejected for arguing balls and strikes.
Yost said there was "a little bit" of a dispute over the strike zone.
"A couple of pitches," Yost said. "Then he wanted to stare into the dugout for another 15 minutes until I muttered another word."
Shields did not think Barry had an enlarged strike zone.
"I don't think so, I don't think so," Shields said. "The front-door cutter to Francoeur, I thought maybe or maybe not. It was really close. But other than that, I thought the pitch to Hosmer was a really good pitch. I mean it was a changeup that was breaking down toward the outside corner. I haven't really looked at it yet, but [Rays catcher Jose Lobaton] didn't really catch it too well, and I think maybe that's what they were looking at. ... But I thought Scott was great back there."
Ben Zobrist drove home the Rays' first run with a sacrifice fly in the third. Jeff Keppinger then gave Tampa Bay a 2-1 lead when he singled to center field.
Shields got some breathing room in the sixth via Ryan Roberts' RBI double. Zobrist drove home another with a double in the seventh to give the Rays a 4-1 lead. After the Royals cut it to 4-3 in the eighth, Lobaton chipped in with a solo home run to center field that expanded Tampa Bay's lead to 5-3, earning the catcher some ice cream in the process.
"I was waiting for the ice cream," teased Lobaton, who again received a treat from Luke Scott like he did after hitting his first Major League home run against Baltimore. "... I hit the ball pretty good, but in this ballpark I was kinda like, 'I gotta run, maybe I can make a triple.' When I hit the ball, I was like, 'I have a chance,' but when I saw the outfielder running, I was like, 'Nah, keep running.' When that ball was gone I was like, 'Oh wow, center field. I'll take it.'"
For the record, dulce de leche was the flavor of the day.
"The one in Baltimore was really good," Lobaton said. "I told Luke, 'Next time, please don't bring that again, I don't really like it.' But I was enjoying that moment."
Maddon didn't have ice cream, but his favorite flavors clearly are Price, as in David Price, and Shields. Price has been the ace of the staff all season, while Shields has looked like the Shields of 2011 lately.
"What [having Price and Shields going well] does, we did use a little bullpen, but it was minimal," Maddon said. "Those guys normally keep the bullpen to a minimum. And of course they give you a really good chance to win the game.
"... They kind of get you well. [You have a] better chance to win the game; better chance to not use a lot of bullpen guys. That's what they permit us to do."
In Shields' last five starts, he is 4-0 with a 2.15 ERA and 34 strikeouts. The Rays have won eight of his last 10 starts, including five in a row.
Maddon believes the Shields of late is the real Shields.
"I think he's going to be like this the rest of the way," Maddon said. "I think he's really trending strongly right now."