Riley Greene struck out swinging and flipped his helmet to the ground.

It was that kind of day. Again.

The Detroit Tigers — for the second day in a row — couldn't get enough production on offense against the lowly Oakland Athletics, losing 7-1.

With Sunday's loss, the Tigers (6-3) dropped two of three to the A's and lost first home series of the season at Comerica Park. The Tigers have lost three of their past four games and scored just one run in their past 18 innings.

What Greene did to his helmet in the fifth inning summarized the frustrations of the day.

His helmet bounced a few times after he flipped it to the ground, following an inning-ending strikeout on a down-and-in slider from right-hander Joe Boyle, who shoved five scoreless innings. He didn't throw strikes and didn't command his pitches, but those issues didn't matter in Sunday's series finale.

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The Tigers just couldn't hit Boyle.

A key opportunity occurred in the first inning, when Parker Meadows drew a walk and Greene hit a single. Spencer Torkelson flew out to center field, which advanced Meadows to third base. The runners were stranded when Kerry Carpenter popped out and Colt Keith grounded out.

In the third, Greene worked a walk, but Torkelson grounded into an inning-ending double play. In the fifth, Zach McKinstry walked, but Meadows and Greene struck out swinging to end the inning.

Boyle, who threw 63% fastballs, walked three batters and struck out six.

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Riley Greene intervenes

The scoreless streak had reached 16 innings.

The Tigers were about to be shut out for the second game in a row until Greene snapped the scoreless streak in the eighth inning with a solo home run to right-center field. He turned on a middle-in curveball from left-handed reliever Kyle Muller in a left-on-left matchup.

It was his third homer and his second pull-side homer.

Greene is on pace for 54 home runs this season.

The A's answered back in the top of the ninth inning, reclaiming the six-run advantage. Seth Brown drove in a run — making it 7-1 — with a line-drive single, one of three hits in the ninth off right-handed reliever Alex Lange.

Jack Flaherty falls apart

It was a tale of two first innings for right-hander Jack Flaherty.

He allowed three hits in a row to open the first inning, all on fastballs: Abraham Toro (single), Zack Gelof (triple) and JJ Bleday (single). He then retired the next three batters, all on fastballs: Brent Rooker (called strikeout), Seth Brown (pop out) and J.D. Davis (swinging strikeout).

The Athletics had a 2-0 lead after the first inning, but Flaherty's real downfall happened with two strikes and two outs in the second inning, when he plunked Toro with an up-and-in fastball to extend the inning. After that, Gelof crushed a two-strike fastball above the strike zone for a three-run home run.

In both matchups, Flaherty had the batters in 0-2 counts before the third pitches burned him.

The homer from Gelof put the A's ahead, 5-0.

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Flaherty allowed six runs on nine hits and one walk with five strikeouts, throwing 62 of 94 pitches for strikes. He took a fastball-heavy approach into his second start, but he abandoned that attack plan for an array of secondary pitches, including his knuckle curve, to pitch deeper in the game.

The A's scored another run off Flaherty in the fourth inning for a 6-0 margin.

Flaherty's four-seam fastball averaged 93.2 mph against the A's, up just 0.1 mph from last year. He generated 14 whiffs (on 40 swings) with four fastballs, six sliders, four knuckle curves.

Gelof finished 4-for-5 and a double shy of the cycle.

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Contact Evan Petzold at epetzold@freepress.com or follow him @EvanPetzold.

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This article originally appeared on Detroit Free Press: Detroit Tigers' offense dormant, drop first series in 7-1 loss to A's