PHOENIX — If the Mets defy the odds and manage to turn around their season, remember this game as the one that saved it.

Down to their final out and trailing the Arizona Diamondbacks 1-0 at Chase Field, Francisco Alvarez took a full-count sinker from closer Andrew Chafin (2-2) and drove it the other way for a game-tying home run. The rookie catcher was absolutely elated when he saw the ball go over the head of right fielder Jake McCarthy as he tossed his bat and leaped in the air, flexing his biceps to the Mets’ dugout as he rounded first base.

The game was tied. Brett Baty continue the rally with a single and Mark Canha tripled off the center field wall to drive in the go-ahead run and give the Mets a 2-1 win.

“You can always count on the theatrics from him,” Canha said.

It was easily the most theatrical win of the season. It was also the Mets’ fourth in a row. The team is now one win away from matching its longest streak of the season and has won two straight series for the first time since May.

It was an impressive atbat by an impressive rookie. Alvarez welcomed the adrenaline.

“It’s my favorite part of the game,” he said. “When that game is on the line, what’s the worst that can happen? You fail. But I’m not afraid of failure. When those moments come up, I’ll come through.”

After doing absolutely nothing against left-hander Tommy Henry and two other relievers, the Mets (40-46) finally broke through before it was too late. It came after a sensational outing by Kodai Senga (7-5), who threw six scoreless innings before surrendering a leadoff home run to cleanup hitter Christian Walker in the seventh. He went eight strong and struck out 12 to tie his career-high mark. He became the first rookie pitcher in franchise history to record multiple starts with one or more strikeouts since Dwight Gooden in 1984.

“With the All-Star Break coming up, I have a lot of days off and I knew I wanted to go deep into the game,” Senga said through a translator. “Being able to do that was special.”

Until the seventh, the Snakes (50-37) managed only two bloop singles and a ball that hit off Jeff McNeil’s glove at second base. They swiped two bags trying to get something going on the basepaths, but after Christian Walker stole second with two outs in the fourth he struck out Lourdes Gurriel Jr. Jake McCarthy hit one off McNeil’s glove to leadoff the fifth and stole second, but Senga struck out the next two and got Alek Thomas to pop one up to center field.

Even after the home run, Senga was able to finish strong, retiring the rest of the side in order and pitching a quick eighth. Buck Showalter was tempted to let him go back out to finish the job.

“I had a pretty efficient eighth inning, so I felt like I could go back out there for the ninth,” Senga said. “But my teammates welcomed me into the dugout with high-fives after the eighth, so I guess that was it.”

The pitch to Walker was the only mistake. Senga left a cutter hanging and Walker nearly hit it all the way to Mexico, blasting it 434 feet into the left-field stands.

“You could tell he felt real comfortable tonight,” Showalter said.

Alvarez’s home run seemed to take the pressure off the Mets. Celebrations like this haven’t come often and they sure haven’t come easy for the Mets, but they handled the wild emotional swings of a crazy ninth inning and were able to hand the game over to closer David Robertson.

Robertson recorded his 13th save of the season with a scoreless ninth. It was almost as if the Mets of old ceased to exist a new team, one more adept at timely hitting and relief pitching, took its place.

“Before this little streak we’re on, it felt like it was going the other way most of the time,” Canha said. “It’s nice to see that it’s starting to go our way. I think it’s a result of a lot of hard work and learning from mistakes. We’re not caving in tough stretches. We’re coming to the field and battling every day.”