NEW YORK -- Even as every reliever around him faltered, even as the Mets’ bullpen around him tumbled to 28th in the league rankings with an ERA creeping toward 6.00, Seth Lugo stayed mostly immune. He was the one relief pitcher on whom the Mets could rely, the one trustworthy option manager Mickey Callaway still had on the other end of his dugout phone.

Now that trust, too, has vanished. Lugo allowed home runs on consecutive pitches in the eighth inning Saturday, transforming a one-run lead into a one-run deficit in the Mets’ 5-4 loss to the Braves at Citi Field. The owner of a 2.23 ERA as recently as last week, Lugo has allowed seven runs in his past three outings to increase that mark by more than 60 percent.

“It’s kind of unexplainable for tonight,” Callaway said.

• Box score

Lugo’s blown save spoiled the big league debut of 29-year-old Chris Mazza, who flourished for four innings after a one-hour, 10-minute rain delay to depart in line for a win. It nullified Jeff McNeil’s RBI doubles in the fourth and sixth innings, which helped give the Mets a middle-innings lead after starter Steven Matz allowed two runs in the first. And it dampened the moods of 40,809 at Citi Field, many of whom had come out to celebrate the 50th anniversary of the Mets’ 1969 World Series championship.

Most pertinently, it extended the Mets’ losing streak to a season-long seven games.

“It’s part of my reality right now,” Callaway said. “This is what it is. You can’t ever give up. You can’t ever throw in the towel. That’s something we all know, and we’ll never do.”

Staked to a one-run lead thanks to Robinson Canó's single that followed McNeil’s second double, Lugo pitched around a two-out double in the seventh inning, reaching 96 mph on the radar gun and striking out two. He fanned another batter in the top of the eighth before Nick Markakis and Austin Riley followed with their homers.

“For me, every loss is difficult,” Lugo said. “When they pile up, it hurts as much as when you lose one. So for me, I’ve got to regroup and come to work, try to be better tomorrow.”

Welcome to the bigs

For eight years, Mazza grinded through the Minors with the same goal as any other young player. But suddenly, Mazza wasn’t young anymore. He entered this season as a 29-year-old who had been released twice, bounced to two independent league teams and wound his way to the Mets organization via the Minor League Rule 5 Draft.

It was an unlikely profile for a savior, but Mazza gave the Mets the type of effort that temporarily lifted them, delivering four one-run innings of relief to depart in line for a victory. With his parents in attendance, Mazza also curried favor from the crowd with a diving attempt at a foul pop in the sixth.

“To finally get here was amazing,” Mazza said. “It was a dream come true. I’m never going to forget it for the rest of my life.”

Matz started the game for the Mets, but he lasted only two innings because of the rain delay. That forced the Mets to turn to Mazza, the reliever in their bullpen most capable of providing length. Shaking off some nerves, Mazza allowed a single and a double to the first two batters he faced before recovering to retire six of his next seven.

“Two hits right away, not how I planned,” Mazza said. “A little bit of nerves and everything. And then once that went away, I had a runner on second with no outs. Now it’s time to compete and find a way to leave him there, and keep it to just one run, keep on giving our guys a chance to win.”