SEATTLE -- Chris Flexen was throwing his fastball perhaps better than he has all season. Unfortunately, his other pitches weren’t quite as effective.

Flexen has been the Mariners' best starter this season. But on Saturday night, he gave up four runs in the fourth inning to put Seattle in a hole it couldn't overcome in a 7-3 loss to Arizona at T-Mobile Park.

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The Mariners are now two games back of the second American League Wild Card spot, which features a tie between the Yankees and Blue Jays. The A’s also lost and remain even with the Mariners.

Although Flexen gave up a run on two walks and a hit in the first inning, he bounced back. The right-hander struck out the side in the second, then retired the D-backs in order again in the third.

“In the second inning tonight, his fastball just jumped. It was crazy how much life he had on the ball,” Seattle manager Scott Servais said. “In the course of it, he got away from a good feeling with his changeup and cutter.”

Flexen, who is averaging 92.6 mph on his four-seam fastball this season, hit 96.3 mph in the second and had seven heaters that hit 95 mph or higher, all but one of which came in the second. However, Flexen usually relies on a mix of changeups, cutters and curveballs along with his fastball.

“Obviously for my sake, you’d like to have all four going,” Flexen said. “Sometimes you only have three, sometimes you’ll only have two. You have to figure out how to still get outs.”

The lack of effective secondary pitches caught up to Flexen in the fourth, when he gave up hits to the first four batters. The D-backs capped the inning with a two-run homer by Daulton Varsho, giving them a 5-2 lead.

“The fourth inning just got away from me,” Flexen said. “Lack of execution, I missed the middle a lot. That’s what you’re supposed to do with those pitches.”

The inning could have been worse for Flexen, though. After giving up four straight hits, Nick Ahmed hit a deep fly ball to left field. José Marmolejos tracked it down, then threw out Pavin Smith, who was attempting to get to third after tagging up.

Flexen's night ended allowing five runs in five innings. It was the first time since July 27 that Flexen (11-6) allowed more than three runs in a start, which had also been the last time he took a loss. Reliever Justus Sheffield also had a tough night, coming on for Flexen to start the sixth and giving up a pair of runs.

After Arizona took a 1-0 lead in the first, Mitch Haniger pushed Seattle ahead with a two-run homer in the bottom of the inning. It was his 31st home run of the season, extending his career high.

Two other offensive bright spots came from a pair of young players. Jarred Kelenic hit a solo home run in the fourth, while Cal Raleigh snapped an 0-for-21 skid with a pair of doubles, his first career game with multiple extra-base hits.

“It feels good, but I’m more worried about how I go up to the plate and how the at-bats go, not necessarily trying to chase hits,” Raleigh said. “I’m trying to focus on the good at-bats.”

While the Mariners lost a game in the AL Wild Card race, they remain in the picture with 20 games to play.

“Unfortunately, these games happen,” Servais said. "I know we want to win every game here down the stretch, but realistically, that’s tough to do. It’s probably not going to happen. We’ve got to come back at it tomorrow.”