ST. PETERSBURG, Fla. -- The nuances of the roof at Tropicana Field came into play twice Friday night, most notably when Kendrys Morales hit a two-run home run off a catwalk, leading the Kansas City Royals to a 3-2 victory over the Tampa Bay Rays.

Morales' two-out swing sent center fielder Kevin Kiermaier scaling the wall in center field, only to see the ball drop onto the field of play, with ground rules making it a home run. The play was reviewed -- hitting a different catwalk can result in a ground-rule double -- but upheld, the difference providing what would end up the winning run.

"I didn't have a view of it. I was watching the outfielder to see if he thought he had a play," Royals manager Ned Yost said. "It looked to me like he thought he had a play. He started getting back and getting back. I never saw the ball. I don't know what it hit."

The teams continued in opposite directions -- the Royals (79-49) won six of their last seven for the best record in the American League and the Rays (63-65) have dropped four of five.

Tampa Bay lost a game in the hunt for the AL's second wild card, dropping 3 1/2 games behind the Texas Rangers.

Royals starter Edinson Volquez (12-7) pitched into the seventh inning, holding the Rays to two runs (one earned) and six hits.

"He got burned early with his offspeed stuff, curveball, but I thought he did a great job navigating through that lineup a couple of times," Yost said. "I thought he pitched a great game."

Royals closer Greg Holland, one night after giving up two runs on three hits in a 25-pitch ninth, worked a perfect inning with just seven pitches for his 29th save of the season.

Officiating played a big role early in the game, with reviews from both managers in the first inning, another on a home run off a catwalk in the top of the third, then a contentious call in the bottom of the third, resulting in the ejection of Rays manager Kevin Cash.

Kansas City led 1-0 in the second on an RBI single by left fielder Paulo Orlando, scoring catcher Salvador Perez, who had singled. The Rays tied the game in the bottom of the second when shortstop Asdrubal Cabrera singled and scored from first on a double to the right-field corner by first baseman James Loney.

Morales' home run -- his 15th of the season -- put the Royals up 3-1 in the third.

"I made a mistake and he's got pop," Rays starter Erasmo Ramirez said. "Whatever was the decision, if it's a double, that's still damage. A homer is just worse damage. I didn't make my pitch."

With two on and two out in the third, the Rays cut the lead to 3-2 when Orlando dropped a pop fly -- lost in the Trop's white ceiling -- in left field for an error.

The tying run would have scored on a ground ball to shortstop by Rays second baseman Logan Forsythe, but he was called out at first base to end the inning. Replays showed he seemed to beat the throw to first, but the Rays had used their challenge, and Cash was ejected after running onto the field to make his case to first base umpire Brian O'Nora. It was Cash's third ejection this season and first since May.

The Rays got help from the bullpen, especially former starter Matt Andriese, who threw three innings of scoreless relief after Ramirez (10-5) lasted only 4 1/3 innings, suffering his first loss in his last six starts.

"No matter how the game is going, you have to back up and do it the way you've been doing, execute better," Ramirez said. "That didn't happen today.

NOTES: Friday was a homecoming game for Royals 2B Ben Zobrist, who spent his first nine MLB seasons with the Rays before being traded to Oakland in January. The Royals acquired him last month, and the Rays paid tribute to him before the game, even having wife Juliana sing the national anthem. Zobrist came in hitting .330 in 26 games with Kansas City -- he was on the disabled list when Oakland came to play the Rays this spring. ... Friday and Saturday's Rays starting pitchers can be traced to a 2012 trade with the Royals, who acquired RHP James Shields. Odorizzi came directly in that trade, as did current Royals LHP Mike Montgomery, who the Rays sent to Kansas City at the end of spring training for Friday starter Erasmo Ramirez.