PHOENIX -- Monday night started out well for the D-backs thanks to Yilber Diaz.

The 23-year-old dazzled in his big league debut allowing just one run over six innings, showing maturity beyond his years as he left with the D-backs leading and seemingly on the way to a victory over the Braves.

That changed in the ninth, though, as closer Paul Sewald allowed a two-out, two-run homer to Sean Murphy that tied the game and the D-backs went on to lose, 5-4, in 11 innings at Chase Field.

It was the third straight blown save for Sewald, who had converted his first 11 chances -- and those are the only three games the D-backs have lost in their last nine.

“Once again, we were one out away from winning a baseball game,” D-backs manager Torey Lovullo said.

Sewald, who declined to speak with reporters after his blown save in San Diego last Friday, left the clubhouse before reporters were allowed in Monday night.

Lovullo said that despite the recent struggles, Sewald will remain the D-backs closer.

“I'm not ready to make that decision,” Lovullo said of giving Sewald a break from save situations. “Paul's been an unbelievable closer for us and he will continue to get the baseball. He's going to get on a nice run for us. There’s going to be some bumps in the road for everybody when you play this game long enough.”

That the D-backs were in position to win the game was in large part because of Diaz, Arizona’s No. 16 prospect per MLB Pipeline.

“He attacked the zone,” Murphy said. “A lot of guys in their debut don't do that. He showed some maturity."

Originally signed by the D-backs for $10,000 at the age of 20 out of Venezuela, Diaz began the season at Double-A Amarillo before being promoted to Triple-A Reno where he made four starts. In his previous start for Reno on July 1, he struck out 13 over six no-hit innings.

After not being signed out of Venezuela when he first tried out for teams at 16 years old, Diaz quit baseball before giving it another shot once again a couple of years later.

At that time, Diaz traveled to the Dominican Republic to try out. Once again, he was not initially signed, but when the COVID-19 pandemic shut down the airports, Diaz was unable to return to Venezuela, forcing him to stay in the Dominican Republic and focus on gaining weight and eating well.

The D-backs eventually signed him on Feb. 5, 2021, and he began his rise through their system.

“I stopped playing baseball for a little bit,” Diaz said through translator Rolando Valles. “And then I picked it up and then once I picked it up, I had a goal and I wasn't going to stop until I achieved that goal. I worked so hard for it and I always was hopeful that it was going to happen.”

When the season started, Diaz wasn’t really on the big league radar for Arizona, but as injuries to the rotation began to mount, the D-backs had to dig further and further into their pitching depth.

After veteran Jordan Montgomery went down with a knee injury a week ago, the D-backs turned to Christian Mena, who started against the Dodgers on July 3.

This time when Montgomery’s turn rolled around, it was Diaz who got the chance, and according to Lovullo, he will start once more when his turn comes around in the rotation again.

“Yilber, making his first appearance at the Major League level, took everything in stride and had a great pregame, and just everything seemed like business as usual to him,” Lovullo said. “And then he goes out there and executes at a very high level and pitches six quality innings against a very [good] offensive team.”