San Diego ? The Kansas City Royals found yet another way to lose.

Rookie Anthony Rizzo hit a two-run single, Tim Stauffer won consecutive starts for the first time this year, and the San Diego Padres beat the Royals, 4-1, Wednesday for their first sweep this season.

The Padres scored four unearned runs with two outs in the third inning thanks to third baseman Mike Moustakas’ error on a sun ball.

San Diego has won four straight and seven of eight. It went 5-1 against Atlanta and Kansas City for its first winning homestand of 2011.

The Royals have lost nine of 11.

“It’s a very weird funk we’re in,” manager Ned Yost said. “We play actually pretty decent baseball most of the time. But we’re not winning baseball games. But the answer is we can turn this around and we can get on a roll with a break here and a break there and get a little momentum going.”

Stauffer (4-5) allowed one run and four hits in seven innings to lower his ERA to 2.97. After going 1-4 with a 3.99 ERA in his first 12 starts, Stauffer has gone 3-1 with a 1.00 ERA in his last five outings.

Heath Bell pitched the ninth for his 23rd save in 24 chances, allowing two singles.

With San Diego trailing 1-0, Stauffer started the decisive third with a popup. First baseman Eric Hosmer lost it in the sun and ducked out of the way. Moustakas, who ran all the way over to the first-base side of the mound, stuck out his glove and the ball bounced off it. He reached out again to try to grab the ball but it hit off his glove again and hit the ground.

Chris Denorfia followed with a single before left-hander Bruce Chen retired the next two batters. Ryan Ludwick doubled to left to bring in Stauffer with the tying run. Rizzo hit a two-run single to right, took second on the throw home and scored on Orlando Hudson’s high chopper.

“It hit right in my glove,” Moustakas said. “I should have squeezed it but it popped right out. I wasn’t able to hang onto it.”

Kansas City scored its run in the top half of the inning when Melky Cabrera doubled with one out and scored on Hosmer’s single to center.

“We’re struggling right now to score runs,” Yost said. “You hate to keep saying it runs in cycles. But it would be nice for the cycle to turn our way pretty quick.”

Chen (4-2), making his second start since May 5, allowed four runs, none earned, and eight hits in six innings. He returned Friday from a stint on the disabled list with a strained back muscle.

NOTES: Chen was facing the Padres for the first time since Aug. 10, 2002, when he appeared in relief with Cincinnati. … The Royals were swept for the sixth time. … The Royals dropped to 0-6 at Petco Park, the only active ballpark in which they don’t have a win. They also were swept here in 2004.