HOUSTON -- Edwin Diaz wasn't supposed to be available. But then again, the Mariners weren't supposed to be thinking about a four-game sweep over the defending World Series champion Astros.
So when Ryon Healy sent Sunday's game into extra innings with a two-out home run off Houston closer Hector Rondon with two out in the ninth, Diaz turned to bullpen coach Brian DeLunas and told him to call the Seattle dugout.
It didn't matter that the flamethrowing youngster had saved the previous three games and needed a well-earned rest. The Mariners are in a postseason chase and after Mitch Haniger's go-ahead RBI double in the top of the 10th, Diaz geared it up again for his Major League-leading 46th save as Seattle topped Houston, 4-3, at Minute Maid Park for its first four-game sweep of the Astros in franchise history.
The Mariners have won six of their last eight games to pull within four games of the Astros in the AL West at 69-50, and they are just 1 1/2 back of the A's in the race for the American League's second Wild Card spot.
"When we tied the game in the ninth, I told Brian, 'Tell them I can pitch today,'" Diaz said. "This was a big series for us, and we have to try to win every game. If I feel good, it's possible I can throw. So I came into the game and tried to help the team win. This was big for us. We are playing the best team in the division. So winning four games, they have to know we have a good team."
One of the reasons the Mariners are good is the phenomenal season of their 24-year-old closer, who is on pace for 63 saves on the year, which would break the MLB record of 62 by Francisco Rodriguez of the Angels in 2008. He already has tied Eric Gagne's record of 24 one-run saves in a season, according to STATS, Inc.
"I will be off tomorrow for sure," Diaz said with a laugh.

"We've run him hard this year, but he understands what this opportunity meant to win that ballgame," Mariners manager Scott Servais said. "It says a lot about him and the tight unit we have here. It's been a struggle. It hasn't been easy for a month or so, but to see this team get it turned around, this is the feeling we had earlier in the year and the timing couldn't be any better."
His teammates knew what it meant for Diaz to step up, as well, after Seattle had lost a 2-0 lead in the eighth before rallying to send the game into extra innings, where they're now 10-1 on the season.

"I got larger goose bumps after hearing that than I did after I hit the homer, to be honest," Healy said. "The fact he wants to call down and come in that game, he feels the energy out there in the bullpen. And obviously he is a humongous part of this team. For him to pick the phone up and say, 'Skip, I'm coming in this game,' I saw him warming up and that's when my heart kind of started to flutter and that's when we got the go-ahead run."
Haniger continued shining in his new leadoff role, as he went 3-for-5 and laced the go-ahead RBI double off Roberto Osuna in the 10th after Dee Gordon's pinch-hit single.

Erasmo Ramirez filled in exceptionally well in his first start in place of Felix Hernandez with five scoreless innings. Ramirez has been sidelined for three months with a strained shoulder, but he came off the disabled list and was outstanding in his first start since April 27. The 28-year-old from Nicaragua allowed three hits with no walks and three strikeouts in 79 pitches.
"This was something huge for me," Ramirez said. "Coming out from a long season and just waiting for this moment to give 100 percent and try to help."
• Ramirez pitches 5 scoreless in return vs. Astros

With setup man Alex Colome unavailable after pitching the previous three games, the Astros overcame a 2-0 deficit by scoring three runs in the eighth off James Pazos and Nick Vincent before Healy answered with his two-out bolt.
"You really dream up those moments," Healy said. "You felt something special kind of the whole game, the way it was going. After the bottom of the eighth inning, I had a gut feeling it wasn't over. Luckily it came true."
Haniger's game-winning hit was his fifth double of the series, tying a Mariners record for a four-game set as he went 9-for-17 with a homer and five RBIs. These four games were his first in the leadoff role with Seattle.
"This was huge," Haniger said. "Every series, every game from here on out is big."
The Mariners wound up beating three Astros All-Star pitchers -- Justin Verlander, Gerrit Cole and Charlie Morton -- and outdueled former Cy Young winner Dallas Keuchel on Sunday. They now head to a crucial three-game set in Oakland, where Robinson Cano will return on Tuesday as the Mariners attempt to chase down the A's in the Wild Card race.
MOMENTS THAT MATTERED
Erasmo escapes: Ramirez breezed through his first four innings before the Astros loaded the bases with no outs in the fifth on a single by Marwin Gonzalez, a bloop base hit to center by Josh Reddick and an error on third baseman Kyle Seager on a hard grounder hit by Tyler White. But Ramirez got Kyle Tucker looking on a 92-mph fastball and then induced a double-play grounder from Martin Maldonado to get out of the jam and preserve a 1-0 lead.
"That was huge to get out of that problem against that team, because they can hit for sure," Ramirez said. "To be able to execute the right pitches at the right moment was huge for me."

SOUND SMART
Diaz became the first pitcher in Mariners history to record a save in every game in a four-game series and just the fourth in MLB history, the first since the Twins' Joe Nathan in 2004. He's also the third reliever in club history with 100 strikeouts in a season, and his 46 saves moves him into second on the Mariners' all-time single-season list, just two back of Fernando Rodney's club record 48 in 2014.
HE SAID IT
"I put a little faith in the Crawford Boxes there off the bat. I knew I didn't get it all. But luckily, it went out." -- Healy, on his 342-foot homer to the short porch in left to tie the game in the ninth

UP NEXT
The Mariners open a crucial three-game series in Oakland on Monday at 7:05 p.m. PT with Marco Gonzales (12-7, 3.79 ERA) facing lefty Sean Manaea (10-8, 3.50) as Seattle tries to close the gap on the A's in the AL Wild Card chase. Gonzales has lost his last two starts -- after winning five in a row -- and gave up 12 hits and seven runs in five innings in his last outing at Texas. But the 26-year-old lefty shut out the A's on two hits over seven innings in May in Oakland in one of his best starts of the year.