Baltimore ? A team tailored to win with offense has put together an impressive run on the strength of its pitching.

Bruce Chen allowed four hits over seven innings, and Brian Roberts hit a leadoff homer to give the Baltimore Orioles a lead they would never lose in a 5-3 victory Saturday over the Kansas City Royals.

Chen (4-1) allowed two unearned runs, struck out three and walked none in winning his third straight start and lowering his earned-run average to 3.12.

“Helping this team has been a great accomplishment for me,” Chen said. “This is where we want to be.”

Over the past four games, first-place Baltimore has allowed a total of four earned runs. Thanks to that kind of pitching, the Orioles have won 11 of 13 to move 11 games over .500 (20-9) for the first time since 1997, their last winning season.

Coming out of spring training, talk about the Orioles centered on a lineup with sluggers Miguel Tejada, Sammy Sosa, Javy Lopez and Rafael Palmeiro. Not many spoke highly about the young pitching staff, but manager Lee Mazzilli knew differently.

“I have thought all along that our pitching is better than people think it is,” he said. “That’s OK, they can think what they want. Our starters, bullpen, they have done an excellent job.”

B.J. Ryan struck out Eli Marrero with the bases loaded and two outs in the eighth, then got three more outs for his seventh save.

Roberts hit the opening pitch from Jose Lima (0-3) over the right-field scoreboard for his ninth homer, four more than his previous career high.

Kansas City pitcher Jose Lima, left, shouts at home-plate umpire Andy Fletcher while being lifted by Royals manager Tony Pena, right, against Baltimore. The Orioles won, 5-3, Saturday at Camden Yards in Baltimore.

“Brian Roberts hits that first-inning home run and I’m up 1-0,” Chen said. “That really helps me, knowing that I’m ahead in the game.”

Mike Sweeney homered and drove in three runs for the Royals, who have lost five straight and 14 of 16. There has not been any finger-pointing in the clubhouse, though, particularly in the direction of manager Tony Pena.

“I don’t care if you bring here the best manager in baseball,” Lima said. “You can bring Sparky Anderson back. You can bring anybody, whoever. Whoever comes here, it’s the same 25 guys. It’s not Tony. It’s not the coaching staff.”

Lima yielded five runs and seven hits in 52/3 innings. He is winless in his seven starts this season.

“I felt pretty good, besides the first pitch,” he said.

After Roberts staked Baltimore to a 1-0 lead, Baltimore pulled away with a three-run fifth. Luis Matos led off with a double and took third on fly ball before Roberts drew a walk. Larry Bigbie followed with a sacrifice fly, and Melvin Mora got an infield hit.

Tejada then lifted a lazy fly ball that left fielder Marrero appeared to have in his sight. But after Marrero backed away at the last second, the ball dropped in front of center fielder David DeJesus and Tejada was credited with a two-run double for a 4-0 lead.

“We ended up both calling for the ball,” Marrero said. “When he hit it up in the air, he hit it right at me. Then it kind of drifted into center field. It’s so loud out there, a lot of fans yelling. We just kind of got caught in between.”

Said DeJesus: “I had no chance. I looked at him, he looked at me. I dove for it. Little things like that cost us two runs.”

The Royals had only three baserunners in the first five innings, none of whom advanced past first base.

In the sixth, however, Roberts botched a two-out grounder to second and Sweeney hit an 0-2 pitch into the left-field seats. It was his seventh homer, the fifth in seven days.

Baltimore made it 5-2 in the sixth when Matos walked with two outs and scored on a double by Jay Gibbons.

Sweeney singled in a run off Jorge Julio in the eighth before Ryan quelled the uprising.

Notes: Baltimore RF Sammy Sosa missed a second straight game because of an abscess on the bottom of his left foot. He is expected to return Monday. … The Royals have gone six straight games without an error, their longest such run since August 2003. … Eleven of K.C.’s last 14 losses have been by two runs or fewer. … Chen has gone at least six innings in each of his six starts.