Astros 8, Blue Jays 6: Chris Carter belted a three-run homer in the first inning and Justin Maxwell and Matt Dominguez launched back-to-back blasts in the fourth as visiting Houston recorded just its fifth win in 24 outings.

Jason Castro had an RBI single during the four-run first and Dominguez and Brett Wallace added two-out RBI singles in the sixth and seventh innings, respectively. Starter Dallas Keuchel (5-5) worked into the eighth for the Astros, who handed Josh Johnson (1-7) his career-worst fifth consecutive loss.

Houston jumped on Johnson in the first inning by stringing together three consecutive singles - with the last by Castro plating Jonathan Villar to open the scoring. Carter promptly gave the Astros a 4-0 lead by depositing a first-pitch fastball over the wall in center for his 19th home run.

Johnson settled down by retiring 10 of the next 11 batters before Maxwell belted a 2-0 fastball over the wall in right-center field to give Houston a 5-2 advantage. Dominguez followed suit by launching a 2-2 fastball over the wall in left for his 13th.

Keuchel served up solo homers to Mark DeRosa and Colby Rasmus before a three-run blast by Jose Bautista forced his exit in the eighth inning. Keuchel allowed six runs on 10 hits in 7 1/3 frames before Jose Veras got the final five outs for his 19th save.

GAME NOTEBOOK: 1B Edwin Encarnacion had an RBI single among his four hits for the Blue Jays, who have dropped eight of their last 10 contests. ... Johnson, who yielded seven runs on as many hits in 5 2/3 innings, has allowed five or more runs in six of his 14 starts this season. He permitted at least five runs on six occasions in 31 starts in 2012. ... Houston 2B Jose Altuve left the game in the seventh inning with tightness in his left quadriceps.