PHOENIX — This was much less the playoff atmosphere in which the Mets found themselves over their previous four games in San Diego, but the quality of opponent was similar and so was the first-day result.

Ultimately, it will be about the results the next two days in this series, but the Mets have been good at openers on this road trip.

Tuesday night they got the entire lineup involved in an 8-3 victory over the Diamondbacks that ended Arizona’s winning streak at six games in front of 22,575 at Chase Field.

The Mets (69-63) are getting close to the point that falling back farther than their three-game deficit to Atlanta for the third spot in the NL wild-card race could render them an afterthought.

The Braves had already won on this night, only increasing the stakes.

But the Mets had a fifth-inning breakout, providing ample cushion for Sean Manaea, who pitched strong into the seventh inning.

Pete Alonso homered, but the beauty of this Mets performance was the manner in which they strung together hits in a fifth inning that didn’t end until 12 batters had come to the plate.

The Mets, who are 3-2 on the road trip, won the first game against the Padres last Thursday, but couldn’t parlay that into a series victory, going loss, win, loss over the next three days.

At minimum, the Mets want to win one of the next two before heading to play the atrocious White Sox.

Manaea took the Mets into the seventh with a shutout intact.

Before departing with two outs in the inning he surrendered three earned runs.

Two of them were delivered by Corbin Carroll, who cleared the left-field fence.

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There were shaky moments over the final 2 ¹/₃ innings, but the Mets got shutout relief from Reed Garrett, Phil Maton, Danny Young and Adam Ottavino.

Alonso’s homer leading off the second gave the Mets a 1-0 lead.

The blast was No. 220 of Alonso’s career, tying him with Mike Piazza for third place on the Mets’ all-time list.

Alonso’s homer was his 28th this season, moving him ahead of Francisco Lindor for the team lead.

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The Mets added an unearned run against Brandon Pfaadt later in the inning.

J.D. Martinez walked and Kevin Newman’s error — he misplayed the throw from Pfaadt on Tyrone Taylor’s comebacker — put runners on the corners.

Jeff McNeil’s RBI fielder’s choice extended the Mets’ lead to 2-0.

Josh Bell’s single leading off the second stood as Arizona’s only hit against Manaea until Lourdes Gurriel Jr. homered leading off the seventh.

In the fourth, Bell connected with Francisco Alvarez’s right wrist on a swing for catcher’s interference.

Alvarez was in obvious discomfort, but remained in the game following a visit from the trainer.

In the top of the next inning, Alvarez delivered an RBI single that put the D’backs in a 3-0 hole. McNeil’s double started the rally.

But the Mets were hardly finished in the inning.

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By the time the frame was complete, the Mets had scored six times to go ahead 8-0.

It was an inning in which the Mets sent 12 batters to the plate and knocked out Pfaadt, who was replaced by Jordan Montgomery.

Mark Vientos stroked an RBI single in the inning and after Brandon Nimmo singled to load the bases, Alonso struck out.

Jesse Winker’s sacrifice fly gave the Mets a 5-0 lead and Martinez’s single reloaded the bases.

Montgomery entered and plunked Taylor on the back foot to force in a run before McNeil walked in another.

Alvarez reached on a fielding error by Geraldo Perdomo for the inning’s final run.