New York Mets starting pitcher Corey Oswalt (55) reacts after...

New York Mets starting pitcher Corey Oswalt (55) reacts after allowing a solo home run to Atlanta Braves starting pitcher Julio Teheran (not pictured) during the fifth inning at Citi Field on Sunday, Aug 5, 2018. Credit: Brad Penner

Tyler Bashlor was both a beneficiary and a victim.

The 25-year-old, who had made the jump from Double-A to the majors in late June, found himself pitching for the Mets against the Braves with the score tied in the 10th inning Sunday afternoon at Citi Field.

Bashlor struck out Freddie Freeman but fell behind 2-and-0 to Nick Markakis, who hammered a middle-in fastball on the next pitch. It sailed over the leaping try of Brandon Nimmo and cleared the right-centerfield wall.

Then the Braves escaped a first-and-third, one-out jam in the bottom of the 10th and held on for a 5-4 victory in front of 27,134.

Wilmer Flores opened the 10th with a double and reached third on Michael Conforto’s groundout to second, but Jose Bautista — who doesn’t have a hit in his last 21 at-bats after going 0-for-5 on Sunday — and Todd Frazier grounded out to end the game. That left Bashlor with his first major-league loss.

“He probably learned a little bit of a lesson tonight,” Callaway said. “He went out there, attacked Freeman with really good stuff and got the strikeout, and he fell behind a really good hitter in Markakis and he backed off his fastball a little bit just to throw a strike . . . You can do that in [the minors]. You can’t do it here.”

“I fell behind, tried to make a good pitch and got hurt,” Bashlor said. He added that he needs to be more locked in at all times.

The Braves took a 4-3 lead on Ronald Acuña Jr.’s RBI single off Seth Lugo in the top of the ninth, but the Mets forced extra innings on Devin Mesoraco’s solo homer in the bottom of the inning. It originally was ruled a double and then was overturned after a 48-second review.

The Mets threatened to extend their 3-1 lead in the sixth as Flores and Conforto opened the inning with singles to put runners at the corners. Bautista then hit a sharp grounder to third baseman Johan Camargo, who threw to second to force Conforto. Flores broke for home on the throw to second and easily was thrown out by Ozzie Albies. Jose Reyes grounded out to end the inning.

Mets starter Corey Oswalt mostly cruised through six innings on 79 pitches — outside of allowing a solo homer by Braves starter Julio Teheran — so Callaway let the rookie go back out for the seventh.

Oswalt immediately struggled. Camargo singled up the middle before Ender Inciarte unloaded on a 1-and-1 pitch, hitting a two-run homer to rightfield to tie the score at 3.

On Saturday night, Bobby Wahl started the eighth inning of the Mets’ 3-0 win before yielding to Robert Gsellman for a four-out save. Wahl, 26, was acquired from Oakland in the Jeurys Familia trade and has minimal MLB experience.

Callaway called this a “good evaluation time for all those young guys,” Bashlor included, and given the trajectory of this season, the Mets will continue to lean on untested relievers.