CHICAGO – Jake Arrieta said he enjoyed running into some of his old Orioles teammates before Friday's game at Wrigley Field.
Then he had an even better time on the mound, shutting down Baltimore in his first start against his former club.
Arietta held Baltimore to four hits in seven innings and Javier Baez homered again as the Cubs beat the Orioles, 4-1.
"There was a little more to it, being your former team," Arietta said. "You know after the first inning, it was just kind of business as usual.
"It was nice to face those guys and see a lot of them again. It's been awhile."
The Orioles traded Arrieta to the Cubs with reliever Pedro Strop in a multi-player deal during last season. He's turned into the Cubs' ace this season.
"A really well-played game all the way around," Cubs manager Rick Renteria said. "The stage was actually set by Jake. Jake did a great job; a phenomenal seven innings of work.
Baez hit his sixth homer in his 18th game since getting called up from Triple-A, Luis Valbuena also homered, and Logan Watkins and Arismendy Alcantara each drove in runs with singles as the Cubs snapped AL East leading Baltimore's four-game winning streak.
Baltimore's Nelson Cruz hit his major league-leading 34th homer, a solo shot off Arrieta (7-4) in the seventh. It came on a change-up that Arietta said "wasn't too bad of a pitch."
Cruz wasn't one of Arietta's teammates on the Orioles, but he had faced the right-hander before.
"I think he looked more mature," Cruz said. "He has command of all his pitches. He doesn't make many mistakes."
Baltimore's Kevin Gausman (7-5) allowed three runs on six hits through five innings, He struck out seven.
Hector Rondon pitched a perfect ninth for his 20th save.
Arrieta retired the first 13 Baltimore hitters before Chris Davis lined a solid single to center with one out in the fifth, one of only two innings when the Orioles managed baserunners against the Cubs' 6-foot-4 right-hander. He struck out five and walked only one.
Valbuena, batting cleanup with Starlin Castro out because of a family emergency, tied a career-high with his 12th homer that put the Cubs ahead, 1-0, in the fourth. Ryan Sweeney doubled one out later, then scored on Watkins' single.
Baez hit a towering shot just inside the left-field foul pole, on a 3-2 pitch with two out in the fifth to make it 3-0.
Cruz ended Arrieta's shutout bid with a homer that reached the left field basket.
Orioles: 2013 Gold Glove-winning 3B Manny Machado, on the DL (right knee ligament sprain) since Aug. 13, has not resumed baseball activities and will not be available when he is eligible to return Aug. 27, Orioles manager Buck Showalter said before the game. "We'll probably have updates in the next two days about where he is, and I'll talk to him today," Showalter said.
Yahoo! Sports reported after the game, citing an unidentified source, that Machado needed surgery and would be lost of the season.
Machado sprained his knee while taking a swing in a game versus the Yankees on Aug. 11. He is hitting .278 with 12 homers and 32 RBIs in 82 games. He missed the first month of the season while recovering from surgery on his left knee.
Cubs: RHP Brian Schlitter, on the DL since Aug. 10 (right shoulder inflammation) has resumed throwing and made a relief appearance with the Cubs rookie league affiliate in Mesa, Arizona, on Thursday night.
Orioles RHP Bud Norris (11-7, 3.69) faces Cubs RHP Kyle Hendricks (5-1, 1.48) at 1:20 p.m. Saturday. Hendricks has six straight quality starts since rejoining the Cubs on July 22.
Including Friday's game Cubs hitters have struck out 104 times in their last nine games. Baez, a free-swinging rookie had fanned 18 times in 33 at-bats. In his 18 games with Chicago, he has fanned 31 times.
"It feels good," Baez said of his homer on Friday. "I know I keep fighting to hit the ball hard. I'm not afraid to strike out, so I'm just going to keep throwing the bat."