"A win is a win," said manager Lloyd McClendon, who watched the final three innings on TV in the clubhouse after getting ejected. "People say you win ugly, I don't buy that. A win is a win. Playing great and losing, you don't get the ice cream for that. We get ice cream tonight. We won. That's all that counts."
Iwakuma's return was the cherry on top of the sundae as the 33-year-old picked up the victory in his debut after missing the first five weeks of the season with a torn tendon in his right middle finger.
Iwakuma's final line didn't look that impressive with four runs on six hits over 6 2/3 innings, but he had a 9-3 lead and had thrown an efficient 81-pitch outing until turning the game over to his bullpen with a runner on first and two out in the seventh.
"Kuma looked like Kuma of old, right off the bat," said catcher Mike Zunino. "I know he's still ironing out some stuff, but I thought his breaking ball and split were great today. Just a couple things with the location of his sinker, but other than that he was pretty impressive for his first time out."
Iwakuma had a string of 25 scoreless innings -- dating back to last year -- snapped when he allowed two runs in the third. But he felt strong throughout and his return bodes well for the Mariners as they regain a pitcher who was third in the American League Cy Young Award voting last season.
"I feel a lot of relief right now," Iwakuma said through translator Antony Suzuki. "I felt very excited before the game and was able to focus and pitch my game, so I'm very happy right now."
And all the Mariners were relieved after surviving the late onslaught, which required closer Fernando Rodney to come in with the bases loaded and two out in the eighth and get out of a Yoervis Medina-created jam to earn what turned into a four-out save.
"However long it was and however many guys we had to use, I'll take a win any day of the week," said Zunino. "We did a great job to limit the damage when stuff wasn't going our way and we were able to squeak out of this one."
The Mariners helped Iwakuma out with their highest-scoring game since a 10-3 victory on Opening Day in Anaheim, though they waited until the late innings to make their presence felt.
After managing just two hits through five scoreless innings against Astros lefty Dallas Keuchel, the Mariners broke through with a run in the sixth and eight more in the seventh as they evened the series at 1-1.
"We were Dr. Jekyll and Mr. Hyde," said McClendon. "The first part of that game we had horsebleep at-bats to be honest with you. The second part of the game, we were a little more patient, got the ball up and got the guy in the strike zone."
A mammoth two-run home run by Justin Smoak and Michael Saunders' two-run double highlighted the seventh-inning outburst, which was kick-started by four straight walks to open the frame by Keuchel and reliever Jose Cisnero as the Astros blew a 2-1 lead in a hurry.
After a bases-loaded walk by Zunino tied the game at 2, Saunders made it 4-2 with his double. Stefen Romero and Robinson Cano followed with run-scoring singles, Kyle Seager added an RBI double and Smoak unloaded a 415-foot blast that hit off the railroad tracks above the left-field stands at Minute Maid Park.
"I hit it pretty good," Smoak said with a smile after notching his fourth homer of the year, with 17 RBIs. "I was looking for the fastball there early and got it and put a good swing on it."
All eight runs came after McClendon was ejected by home-plate umpire James Hoye after becoming upset about the Astros getting extra time to warm up Cisnero in the bullpen following a mound visit by Houston skipper Bo Porter and another by catcher Jason Castro.
The Mariners have won six of their last eight games to improve to 13-15. Houston, which had beaten Seattle three of their first four meetings this year, fell to 10-20.
Iwakuma breezed through the first two frames before giving up two runs in the third on an RBI triple by Jonathan Villar and sacrifice fly by Jose Altuve. The Astros cut the lead to 9-4 on a home run by Chris Carter in the seventh and then began chipping away at Seattle's bullpen after Iwakuma's departure.
Rookie reliever Dominic Leone surrendered a two-run homer to Villar in the seventh as Houston scored four times in that frame, then made it 9-8 with a pair of runs off Medina and had the bases loaded before Rodney was summoned for his seventh save.
Saunders, Cano and Smoak each had two RBIs and the Mariners went 5-for-7 with runners in scoring position to take advantage of nine hits and five walks.