PHOENIX — His manager wanted curveballs, so Mets starter Dillon Gee gave him curveballs. Before the game, Terry Collins wondered aloud why Gee refused to open up his arsenal. Don’t only throw fastballs, Collins warned.

Gee chose as his target Justin Upton, the Arizona Diamondbacks star, and flung a first-pitch hook for a strike in the first inning tonight at Chase Field. Three pitches later, he tried again. This time, Upton unloaded for a solo home run that set the tone for this 4-3 defeat to the Diamondbacks.

Gee (10-4, 4.07 ERA) deposited the Mets (58-60) in an early hole during his five innings of work. The final three were clear, but the first two were calamitous enough to wreck the evening.

After his curveball was punished, he placed a premium on his fastball in the second. That went poorly. He plunked, and broke the hand of, former Met Xavier Nady, then surrendered a pair of doubles on elevated fastballs to Sean Burroughs and Cody Ransom.

The coup de grace occurred with the next batter, former Yankee prospect Ian Kennedy. As Gee toed the rubber, Kennedy squared to bunt. With the count 1-0, he pulled back and muscled a double over the head of center fielder Angel Pagan, who had returned to the lineup after missing a game due to back spasms.

The offense did Gee few favors. They stranded two runners in the third. They left the bases loaded in the fourth. They managed just one run off Kennedy, when Jason Bay ripped an RBI single in the fifth. Bay scored again in the eighth after pulling a double down the left-field line. The final run came in the ninth, when Scott Hairston hit a leadoff double and was brought home soon after.

It was a disappointing evening for this group, who remain reeling from the dual loss of Daniel Murphy and Jose Reyes. In this recent skid, the offense has been quiet, the defense sloppy and the pitching inexact. Gee continued that trend.

No longer is he the darling of this staff, the Triple-A call-up who doubled as a rotation savior in April and ran off seven victories before experiencing his first defeat. He is back to being, well, Dillon Gee, the 21st round draft pick with the 4.96 ERA in Buffalo last season.

His place in the rotation is not in jeopardy. The realistic replacement are still years away, stashed in Double A (Matt Harvey) and Class A (Zack Wheeler). Gee will be counted on for these next two months, and perhaps next season as well. The Mets will have to live with the results.