BALTIMORE (Interstat) — Pete Alonso homered, Adley Rutschman drove in two runs, and the Baltimore Orioles defeated the Houston Astros 5-3 on Tuesday night at Oriole Park at Camden Yards.

Shane Baz allowed one run in 5 2/3 innings to earn his first victory since Baltimore acquired him from Tampa Bay in December as the Orioles won the opener of a three-game series. Brice Matthews hit his first home run since March 30 as part of a three-hit night for Houston, which fell to 11-19 and tied a season-high eight games under .500. The Astros were 2 for 14 with runners in scoring position.

Baltimore improved to 14-15 and snapped a two-game losing streak. The Orioles had been outscored 22-4 in consecutive losses to Boston over the weekend.

Baz (1-2) struck out six, scattered six hits and walked two. He lowered his ERA from 8.31 to 6.52 with his best outing of the season, coming off back-to-back losses in which he allowed four earned runs each.

Ryan Helsley pitched a perfect ninth inning for his seventh save, striking out one. The Orioles’ bullpen combined for 3 1/3 scoreless innings, with Andrew Kittredge striking out three over one hitless inning and Rico Garcia recording one out on strikeout.

Kai-Wei Teng (1-2) took the loss for Houston. The right-hander allowed two runs on five hits over three innings with two strikeouts and one walk. Ryan Weiss gave up three runs on two hits over 3 2/3 innings, including Alonso’s go-ahead home run. Bennett Sousa struck out three in a scoreless inning, and Steven Okert allowed two hits but no runs in one-third of an inning.

The game turned in the fifth inning. With the score tied 2-2 after Matthews’ solo home run in the top half, Alonso launched a two-run homer to right-center field off Weiss, scoring Taylor Ward and giving Baltimore a 4-2 lead. The ball carried over the wall on a fly ball to right center, his fourth home run of the season.

Baltimore added insurance in the seventh. Gunnar Henderson walked, stole second and scored on Rutschman’s single to center field, extending the lead to 5-2.

Houston mounted a rally in the eighth. Christian Walker led off with a double, moved to third on a groundout and scored on Dustin Harris’ triple to right field. Harris then scored on Matthews’ single to right, cutting the deficit to 5-3. But the Astros could not complete the comeback. With two runners on and two outs, Carlos Correa struck out swinging against Kittredge.

The Astros threatened again in the seventh, loading the bases with one out on singles by Cam Smith and Matthews followed by an intentional walk to Yordan Alvarez. But Kittredge struck out Isaac Paredes and Jose Altuve to escape the jam.

Houston outhit Baltimore 11-9, but stranded 10 runners. Matthews finished 3 for 4 with a double, home run and two RBIs. Walker doubled and scored once. Harris tripled and drove in a run.

Alonso’s two-run homer and a double by Samuel Basallo that drove in the Orioles’ first run were key early blows. Basallo doubled in the first inning to score Rutschman, who had singled Henderson home earlier. Henderson doubled and scored twice.

The Astros scored first in the fifth. Matthews crushed a 2-1 pitch from Baz over the right-center field wall for his second homer of the season, tying the game 2-2. It was his third hit of the night and extended his hitting streak to four games.

Houston had runners in scoring position in the second, third, sixth, seventh and eighth innings but could not deliver the big hit. The Astros went 2 for 14 with runners in scoring position and left 10 men on base.

Baltimore’s defense helped preserve the lead. In the fifth, Coby Mayo made a tough play on a grounder by Yainer Diaz, and shortstop Gunnar Henderson handled several hard-hit balls up the middle. The Orioles turned one double play.

Teng worked around trouble in the first two innings but escaped. He allowed a double and a single in the first but got a pickoff at first base in the second to erase a single. The Orioles scored twice in the first on four hits, including doubles by Henderson and Basallo.

Houston starter Weiss entered in the fourth and retired the first four batters he faced before Alonso’s home run.

Baz departed after 5 2/3 innings, having thrown 74 pitches, 49 strikes. He threw first-pitch strikes to 14 of the 24 batters he faced and recorded 12 swings and misses.

Helsley retired the side in order in the ninth on 14 pitches, earning his seventh save in eight opportunities.

Houston returns to Camden Yards for the second game of the series Wednesday, while Baltimore looks to build its first winning streak since April 22-24.

The Astros have lost four of their last five games and remain in last place in the American League West, 7 1/2 games behind first-place Seattle.

Baltimore snapped a two-game skid and moved within one game of .500 for the first time since April 22.

The game drew 13,233 fans and lasted 2 hours, 36 minutes.

Interstat’s game simulator had projected a final score of Baltimore 4, Houston 3. Interstat’s ELO system gave the Orioles a 51.60 percent probability to win. Baltimore was installed as a pregame favorite with a spread of minus-1.5. The total score of 8 went over the over-under line of 9.