KANSAS CITY, Mo.(AP) Rick Porcello is comfortable now, all settled in after a shaky start to his big league career.

Porcello won his fifth straight start, Placido Polanco homered and drove in three runs and the Detroit Tigers beat the slumping Kansas City Royals 8-3 on Wednesday.

Porcello (6-3) allowed two runs and four hits in six innings. The 20-year-old rookie lost three of his first four starts. But in his last five, covering 30 innings, he's allowed five runs and struck out 20 while beating Minnesota, Cleveland, Oakland, Colorado and Kansas City. His ERA over the span is 1.50.

''He's been watching film, watching tape of the hitters,'' manager Jim Leyland said. ''He does his homework. He wants to learn, and that's always a good sign.''

The right-hander is the first Detroit rookie to record five wins in May since at least 1954. He's the first Tigers pitcher with five wins in May since John Doherty in 1994.

''I just think I'm doing a better job of getting my breaking ball over for strikes and kind of giving hitters a different look that way, to keep them of my fastball a little bit,'' Porcello said. ''I think that's the biggest thing so far. I'm just going to keep working on it and getting better.''

Porcello said he is gaining confidence with each win.

''I've had a couple of starts now and I'm able to settle in a little better out there and focus. And all the jitters are kind of gone,'' he said. ''I think I'm getting a little more comfortable with each start.''

In taking two of three from the Royals, the Tigers lost only to Zack Greinke and increased their lead over KC in the AL Central to four games. The Royals, after a promising April and early May, have lost 13 of 18.

Bench coach John Gibbons managed the Royals while Trey Hillman served a one-game suspension imposed by Major League Baseball for spitting in the face of umpire Paul Emmel on Monday.

''Porcello was very good,'' Gibbons said. ''He's got that dominating sinking fastball. Sometimes, it is tough to do anything with that. He comes as advertised. He's a big arm out of high school, a young kid that got here fast. He's impressive.''

Josh Anderson , the Tigers' leadoff hitter, had four hits. He singled in Ryan Raburn in the fifth before Polanco connected against Kyle Davies (2-4) to give Detroit a 5-2 lead.

Miguel Cabrera clubbed a towering home run off a 3-2 pitch from Davies leading off the second.

Davies gave up eight runs and 10 hits in 5 2-3 innings, letting the leadoff batter reach every time he went to the mound. Three of the runs were unearned because of third baseman Mark Teahen 's error in the three-run sixth.

Teahen had three hits, including his sixth homer, and Luis Hernandez singled in a run in the seventh for Kansas City.

David DeJesus tripled and scored on Billy Butler 's single in the first to give Kansas City a 1-0 lead but Cabrera tied it with his 10th homer. Curtis Granderson singled after Cabrera's drive, advanced on a sacrifice and stole third. He scored on Raburn's two-out single to make it 2-1.

Notes: Polanco is hitting .333 at Kauffman Stadium. ... Tigers play-by-play voice Dan Dickerson flew home to have surgery on his left leg. The veteran broadcaster hurt himself while jogging near the team hotel on Tuesday. ... CF Coco Crisp , who left Tuesday's game with a sore shoulder, hopes to be back in the Royals' lineup by Friday. ... Joakim Soria , KC's All-Star closer, threw 15 pitches in a simulated game in Arizona on Wednesday and said the sore shoulder that sent him to the 15-day DL felt fine.