BALTIMORE (Interstat) — Matthew Boyd pitched six innings of four-hit shutout ball and the Chicago Cubs defeated the Baltimore Orioles 5-2 on Tuesday night at Oriole Park at Camden Yards, improving to 51-40 while dropping the Orioles to 42-50.

Boyd, who allowed three walks and struck out six, earned his fourth win against one loss. He left with a 3-0 lead after the top of the sixth, though the Orioles mounted a two-run rally in the seventh off reliever Tyler Ferguson. Trent Thornton pitched a scoreless ninth for his second save of the season.

Shane Baz took the loss, falling to 4-9. The right-hander worked six innings, allowing six hits and three earned runs with three strikeouts and two walks.

The Cubs broke a scoreless tie in the third inning. Miguel Amaya walked with two outs and Pete Crow-Armstrong singled to center, putting runners at first and second. Alex Bregman then lined a single to center that scored Amaya, with Crow-Armstrong advancing to third. Michael Busch walked to load the bases, but Seiya Suzuki popped out to shortstop Gunnar Henderson to end the inning.

Chicago added two more runs in the fifth. Dansby Swanson led off with a single to left. Amaya doubled to center, sending Swanson to third. Crow-Armstrong singled to right, driving in Swanson and moving Amaya to third. After a successful challenge overturned a force out call at first, Bregman grounded into a fielder’s choice that allowed Amaya to score, making it 3-0. Busch walked again, and Suzuki grounded into an inning-ending double play.

The Orioles threatened in the bottom of the fifth but could not score. Taylor Ward walked with one out, but Adley Rutschman grounded into a double play to erase him.

Boyd navigated a two-hit fourth inning, striking out the side around a hit by pitch and a single. The left-hander allowed only one runner past second base in his outing, that being in the fourth when Pete Alonso singled and Coby Mayo was hit by a pitch, but Boyd struck out Samuel Basallo, Blaze Alexander and Dylan Beavers to end the frame.

The Cubs extended their lead to 4-0 in the seventh. Amaya singled to left off reliever Keegan Akin. Crow-Armstrong flied out, then Bregman doubled to center, putting runners at second and third. Busch lifted a sacrifice fly to left, scoring Amaya.

The Orioles answered in the bottom of the seventh against Ferguson. Basallo singled to first, and Alexander lined a single to right to put runners at the corners. Tyler O’Neill, pinch-hitting, was called out on strikes after a successful challenge by the Orioles overturned an initial pitch result. Leody Taveras struck out, but Taylor Ward walked to load the bases with two outs. Rutschman then singled to right, driving in Basallo and Alexander. Right fielder Suzuki’s throwing error allowed Rutschman to take second, but Gunnar Henderson struck out to end the inning with the score 4-2.

Chicago added a crucial insurance run in the eighth. Nico Hoerner singled to center off reliever Nick Raquet. Michael Conforto grounded out, moving Hoerner to third. Swanson lined a single to right, scoring Hoerner and making it 5-2.

Thornton worked a 1-2-3 ninth, striking out O’Neill and getting groundouts from Alexander and Taveras to close the game.

Key performances included Rutschman’s two-run single in the seventh, his second hit of the night. Bregman went 2-for-5 with a double and a run batted in. Swanson had two hits and drove in a run. Crow-Armstrong had two hits and an RBI. For the Orioles, Henderson had one hit in four at-bats. Baz pitched effectively but took the loss.

The two-game series continues Wednesday and Thursday before the Cubs travel to Cincinnati and the Orioles host Kansas City. Chicago returns home to face Minnesota after the All-Star break.

Interstat’s game simulator had projected a final score of Chicago Cubs 7, Baltimore Orioles 4. Interstat’s ELO system gave the Cubs a 54.40 percent probability to win. Chicago was installed as a pregame favorite with a spread of minus-1.5. The total of seven runs went over the over-under line of nine.