DETROIT -- Justin Verlander has spent all season trying to recapture the form that made him perhaps the best pitcher in baseball in 2011 and 2012.
Now, with another postseason berth in sight, the Detroit right-hander hopes he's finally turning a corner.
"It seems like the whole year has been tinkering," Verlander said. "I feel like the last three starts, I've found what I really need to be working on and focusing on."
Detroit remained six games ahead of second-place Cleveland in the AL Central and dealt the third-place Royals a setback in the postseason race.
Kansas City is one of several teams hoping at least to catch Tampa Bay for a wild card.
Verlander (13-11) allowed three runs and nine hits in 6 2/3 innings. Three relievers finished. Joaquin Benoit worked out of a bases-loaded jam in the eighth and got the final four outs for his 19th save in 19 chances.
Bruce Chen (7-3) allowed five earned runs and seven hits in 4 1/3 innings.
"They had a really good plan going in. They were hacking early," Chen said. "They prepared themselves really well."
The Royals, who are trying to make the playoffs for the first time since winning the World Series in 1985, fell 3 1/2 games behind the Rays after this series against the leaders in Kansas City's division did not start well.
Kansas City fell behind 6-1 in the fifth, and although the Royals rallied, Detroit's bullpen was able to hold on. With the score 6-3, Detroit's Drew Smyly issued a one-out walk to Eric Hosmer in the eighth, then Jose Veras came on and walked Billy Butler on four pitches. After taking ball one, Salvador Perez popped out, but Veras hit Mike Moustakas to load the bases.
On came Benoit, who has been excellent since becoming Detroit's full-time closer. He struck out David Lough to end the threat.
Kansas City left fielder Alex Gordon overran Austin Jackson's leadoff double in the Detroit first for an error, allowing Jackson to advance to third. He scored on Torii Hunter's groundout to give the Tigers a 1-0 lead.
Kansas City tied it in the fourth on an RBI single by Perez, but Fielder's flyball in the bottom of the inning barely cleared the wall in the right-field corner for a two-run shot. It was his 24th homer of the year.
Like Verlander, Fielder has had his struggles this season, but he now has 102 RBIs, the sixth time in seven years he's reached 100.
"If I'm healthy and can play every day, that's what I'm really focused on," Fielder said. "When you're out there every day, you've got a chance to do all those things."
The tiebreaking home run came after banged-up slugger Miguel Cabrera led off with a double to right-center that Lough just missed making a sliding catch on. It was Cabrera's first extra-base hit since Aug. 26.
Detroit added three runs in the fifth. Hunter hit a two-run single, and after an intentional walk to Cabrera, Hunter caught the Royals napping and broke for third. Chen was called for a balk, giving Hunter third and Cabrera second, and Fielder's RBI single made it 6-1.
Verlander has pitched well in 2013, just not up to the terrific standard he set the previous two years. The Tigers are hoping the right-hander will find a groove late this season, and he was breezing along until the Royals rallied with a couple runs in the sixth. Butler's RBI single made it 6-2, and Perez drove in Butler with a double.
But Verlander was happy overall after striking out seven without a walk.
"I feel like I'm pretty doggone close," said Verlander, whose ERA is at 3.66. "I think my stuff's been a lot better. Tonight I made a little bit of an adjustment with my grip on my curveball and that seemed to be working really well for me."
Cabrera has been bothered lately by a strained abdomen, among other nagging injuries. Detroit manager Jim Leyland said before the game his third baseman looks better now. ... The Tigers sent RHP David Paulino to Houston as the player to be named in the deal that brought Veras to Detroit in July. ... Butler went 2 for 3 off Verlander and is now 30 for 68 (.441) off the Detroit star. ... Kansas City's bullpen retired all 11 batters it faced, including seven strikeouts. ... Detroit RHP Doug Fister (12-8) faces Kansas City RHP Ervin Santana (8-9) on Saturday night.