Mets general manager Sandy Alderson told Robert Gsellman he needed to ramp up his game when he was rehabbing with Double-A Binghamton.

After words were exchanged and Gsellman fired back with a flippant “I don’t care,” the two reconciled and the 24-year-old got to work.

In a night where the focus was on Steven Matz, the right-hander went 6 1/3 strong innings, allowing one run on five hits while striking out three.

“There are no guarantees ever that you are going to start the season, especially with young power pitching, where you are going to say these guys are going to be healthy throughout the season,” said Mets manager Terry Collins.

While his offense didn’t have his back on Monday, going 2-for-12 with runners in scoring position, it was a positive outing for Gsellman who has had an overall disappointing season.

The Mets put Diamondbacks starter Taijuan Walker in danger the first four innings, including loading the bases in the second, but failed to capitalize.

Arizona plated the first run of the game on a single from J.D. Martinez that scored Jake Lamb from second after he walked earlier in the inning.

In the seventh with the Mets still trailing 1-0, Travis d’Arnaud led off the frame with a double and promptly moved to third on a sacrifice bunt from Brandon Nimmo.

The following two batters walked to bring the big man, Yoenis Cespedes, to the dish.

La Potencia ripped a base hit into left field to score d’Arnaud, but Asdrubal Cabrera was tagged out on a bang-bang play at the dish.

After the Mets challenged, the call on the field was upheld and the score remained tied.

The cast of Jerry Blevins, Paul Sewald and AJ Ramos combined to fire 2 1/3 scoreless innings in relief of Gsellman. But in the tenth, Erik Goeddel came on and was erratic, walking Gregor Blanco to start the inning and served up the fatal blow when A.J. Pollock took him deep two batters later.

Michael Conforto brought the Mets back within one in the bottom of the 10th, but it would prove to be too little, too late as the Mets dropped their seventh game in the last eight matches.

With Matz out the remainder of the season and set to undergo surgery to correct his ulnar nerve in his throwing elbow, Tommy Milone will get the ball for the Mets tomorrow and will hope to avoid being snake bitten by the Diamondbacks yet again.