SEATTLE — As the Phillies opened a seven-game West Coast trip here Monday night, they had a higher rate of hard-hit balls than any team in the National League but only the eighth-most runs scored.

Joe Girardi’s engineering degree isn’t required to realize that something doesn’t add up.

But the biggest source of the manager’s frustration is also his greatest reason for optimism. To a man, the Phillies believe they will hit, at least relative to the rest of the league. And if they hit, they think they can finally push through to the playoffs.

Consider this, then, to be a demonstration of what they can do. The Phillies rapped out a season-high 17 hits and scored their most lopsided victory so far this season, 9-0, over the Seattle Mariners in the opener of a three-game series.

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And the biggest swing among all the big swings — from a tone-setting solo home run by ex-Mariner Jean Segura, to three hits apiece from Bryce Harper and Nick Castellanos, and two J.T. Realmuto RBI singles — came when Rhys Hoskins pulled in his hands and hit an inside curveball for a homer in the second inning.

“They always feel good, regardless of when they come or how they come, right?” Hoskins said. “But yeah, it felt great.”

Hoskins, as much as anyone, has symbolized the Phillies’ luckless offense. Entering the week, he ranked in the 97th percentile among all hitters in average exit velocity (97.5 mph) and the 89th percentile in hard-hit rate (51.6%).

Yet he was batting .189 with two homers and a .638 on-base-plus-slugging and got dropped to seventh in the batting order.

So, yes, after falling down two strikes against Mariners starter Chris Flexen and fouling off two tough pitches, Hoskins needed the at-bat to end with him driving a ball over the left-field wall to open a 2-0 lead.

Hoskins needed the seventh-inning RBI single, too, and the leadoff single in the ninth. The three hits matched his total from his previous five games. He was 5-for-39 entering the game.

“I was actually talking to him about it today about sometimes how much this game stinks,” Girardi said. “You make hard outs and sometimes it doesn’t seem fair. But it’s the game, and you’ve got to find a way to grind through it.”

It’s enough to make a good hitter go mad.

Hoskins has tried to find his sanity in the batting cage. He’s putting in extra work with hitting coach Kevin Long. His message, according to Hoskins: “Make moves smaller.” Hoskins is hitting the ball hard. Long’s minimalist approach is designed to keep him from changing too much.

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“It’s working a lot on just trying to simplify things, really,” Hoskins said. “Whether or not it’s actually coming out that way, I think it’s the thought process that gets me there. It’s just allowed me to see the ball a little bit better, a little bit longer, and make decisions later. It’s all what it’s designed to do. It’s nice to see some hard work paying off.”

The reeling Mariners, losers of 11 of the last 13 games, are a good antidote for the Phillies, who arrived having had lost five of six games. It’s about to get more difficult. The Phillies are due to face reigning American League Cy Young winner Robbie Ray on Tuesday night and Logan Gilbert, who has posted a 1.36 ERA in six starts, on Wednesday before going to Los Angeles and likely facing Clayton Kershaw and Walker Buehler in a four-game series at Dodger Stadium.

The Phillies were built to slug, and with Zack Wheeler and Zach Eflin away from the team and on the COVID-19 injury list, that formula must apply more than ever. Best to get the offense going now, then. Maybe it will even carry them through the week.

“Totally,” Hoskins said of the importance of winning a laugher. “To come out here and kind of make the first punch, so to say, is something that we’ll try to ride that momentum into the next couple of days.”

Segura in Seattle

Playing here for the first time since the Mariners traded him to the Phillies on Dec. 3, 2018, Segura started the scoring by lining a solo homer to center field against Flexen in the second inning.

Segura had two solid seasons in Seattle, batting .302 with 21 home runs in 269 games and going to the All-Star Game in 2018. But he also brawled in the clubhouse with teammate Dee Strange-Gordon and got benched late in the 2018 season for not hustling.

When the Mariners chose to rebuild after 2018, they sent Segura to the Phillies in a five-player swap that netted shortstop J.P. Crawford, whose hot start has been interrupted by back spasms.

» READ MORE: J.P. Crawford for Jean Segura: Reassessing the Phillies-Mariners trade four years later

No danger, Ranger

Overshadowed by all the offense were six scoreless innings from left-hander Ranger Suárez, who worked out of two-on, none-out jams in the second and sixth innings. He also got out of a two-on, two-out situation in the third.

“I tried to locate my pitches,” Suárez said through a team translator. “I was just looking for a double-play ground ball, something like that, to get out of the innings quick.”

Including Suárez’s outing, Phillies starting pitchers have allowed 34 earned runs in 106 innings for a 2.89 ERA over the last 19 games.

Morales shines in debut

One day after getting called up from double-A Reading, reliever Francisco Morales faced six batters and recorded six outs in his major-league debut.

Morales struck out Jarred Kelenic and Cal Raleigh in the seventh inning and got touted rookie Julio Rodriguez to bounce into a double play in the eighth after a leadoff walk to Ty France.

“I always imagined myself striking out the first batter I faced,” Morales said through a translator. “That was really my goal, and I accomplished that. It happened. It was great.”

Morales’ wife, Oriana, flew to Seattle from Philadelphia on Monday morning and was in attendance to watch him pitch.