Rookie catcher Travis d’Arnaud hit his first big league home run in the fourth inning of yesterday’s blowout 11-3 loss to Detroit.

“I just put my head down and started running and the fans let me know it was gone,’’ said d’Arnaud, who added he felt, “speechless. I felt an unbelievable feeling. But we got the loss, so it’s bittersweet.’’

D’Arnaud hit a Rick Porcello 1-0 pitch that carried just far enough to clear the wall in left-center, reaching the Party City Deck for a two-run shot and a 3-2 lead.

“Everbody’s happy for him. We’re all excited for him and excited that he’s here, and that he hit the homer. But we didn’t win, so …,’’ manager Terry Collins said, trailing off.

The highly regarded young catcher — acquired in the offseason from Toronto in the deal for Cy Young winner R.A. Dickey — had been 1-for-16 before the homer. The crowd of 32,084 stood and cheered until he stuck his head out of the dugout for his first curtain call.

“I didn’t see it coming. I’m very grateful to the city of New York for that,’’ said d’Arnaud, who had to be prompted by veteran teammates to take his curtain call. “Yeah, a few of the guys did. I didn’t know what’s going on. It’s an unbelievable experience.’’

* The Mets had been held scoreless for 20 straight innings before Daniel Murphy’s broken bat RBI single in the third.

They were 1-for-4 with runners in scoring position, and are 5-for-34 in such situations over their last five games.

* Lucas Duda, who was recalled on Saturday, drew an eighth-inning pinch-hit walk in his first big league plate appearance since June 21. After going on the disabled list with an intercostal strain, Duda had been optioned to Triple-A Las Vegas.

* Wilmer Flores got yesterday off with the Mets trying to rest his injured right ankle, which he sprained on Aug. 12. Collins said it may not be 100 percent all year. … Collins also said the Mets are trying to best figure out how to spare Matt Harvey, who allowed a career-high 13 hits Saturday. Harvey acknowledged he’s “pretty tired” after having already thrown a career-high 178 1/3 innings.