KANSAS CITY, Mo. (AP) — The Royals were zipping along in playoff contention a little more than a week ago, a rare feeling indeed for a franchise that hasn't been to the postseason in more than two decades.

Well, things are starting to feel a little more like normal.

Dayan Viciedo hit his second career grand slam to highlight a five-run inning for the White Sox, and Andre Rienzo picked up his first career win for Chicago by shutting down the punchless Kansas City offense in a 5-2 victory Wednesday night.

It was the fourth straight loss for the Royals, and their seventh loss in nine games — four of them coming against the Marlins and White Sox, both teams in last place in their divisions.

Four games out of the wild card a little more than a week ago, the Royals are fading fast.

"You just have to keep battling through it, keep grinding through it," Royals manager Ned Yost said. "You have to keep grinding through it because you don't know when you're going to break out of it. It seems like when we go into these offensive funks, we do it as a team and then all it takes is one big hit and here we go again. They're battling through it.

By the time they get through it, it may be too late to matter.

"There's no rhyme or reason," designated hitter Billy Butler said. "We're in a tough stretch and we're just not hitting. We're not getting guys in when we have them in position."

On this night, it was Rienzo (1-0) who took a turn breezing through the Royals.

The 25-year-old from Sao Paulo, one of just two Brazilians in the big leagues, didn't allow a hit until back-to-back singles in the fourth. He allowed another in the fifth and two in the sixth.

Otherwise, he was basically untouchable — just as he had been in the minors.

After rocketing through two levels last season, Rienzo began catching the eye of White Sox brass at Triple-A Charlotte. He was 4-0 with a 1.23 ERA over his last four starts, including a no-hitter on July 25 — just before his call-up to the big league team.

Rienzo's rise hasn't been without controversy, though. He was suspended for 50 games early last season after testing positive for a performance-enhancing substance.

"Brazil is just about soccer. I'm trying to open doors," said Rienzo, who picked up the game after watching his mother play softball as a kid. "It's all soccer, soccer, soccer. I hope that I will open doors and people will see more guys playing baseball."

Rienzo allowed only a sacrifice fly to Mike Moustakas while cruising through six innings to win for the first time in five starts. The Brazilian right-hander allowed just five hits and two walks in helping the White Sox win their season-best fifth straight game.

Addison Reed worked the ninth for his second save of the series and 33rd on the year.

Viciedo's grand slam off Jeremy Guthrie (12-10) in the fourth followed an RBI single by Adam Dunn that had given the White Sox the lead. Their five runs in the frame matched the number of runs the Royals' woeful offense had mustered in the previous 22 innings.

David Lough drove in another run for the Royals in the sixth, but that was all they managed in another lackluster offensive performance. They finished with six hits on the night.

Guthrie gave up that many hits by the fourth inning.

The Royals' right-hander threw 72 of 100 pitches for strikes, an exceptionally high rate. The problem was that he couldn't make anybody miss. The White Sox pounded out nine hits off him.

After winning four straight, Guthrie has been savagely roughed up in his last three starts. He gave up five runs on 10 hits in a loss to Boston a couple weeks ago, and four runs on a career-high 13 hits at Detroit in another defeat his last time out.

"I made some pitches they were able to get some bats on and get some hits. I dug myself into a big hole," Guthrie said. "These guys are a major league team that hits the ball well. If you make mistakes they'll make you pay."

NOTES: Viciedo finished with three hits for Chicago. ... Guthrie threw a pitch in the second inning that slipped past C Salvador Perez and got lost in the padding around advertisements behind home plate. The exact same thing happened to a passed ball thrown by Royals RHP Ervin Santana the previous night. ... White Sox LHP Jose Quintana goes to the mound in the series finale on Thursday night. RHP James Shields gets the start for Kansas City.