LOS ANGELES -- The last time Ryne Nelson pitched behind an opener at Dodger Stadium, it was a winning formula. And it seemed like Tuesday night’s game was going to play out similarly for the D-backs.

But things got away from closer Paul Sewald in the ninth inning, as he allowed two runs for a 6-5 walk-off loss to the Dodgers and his first blown save of the season in his 12th opportunity.

"I trusted my players. We just didn’t execute, and that's what it comes down to,” said manager Torey Lovullo. “A good hitter beat a really good closer. It's part of the game."

For the D-backs this season, the opener strategy has been a way of trying to protect right-handed starters -- including Nelson twice -- from an extra time facing the powerful left-handed bats of Shohei Ohtani and Freddie Freeman.

On May 22, it was Brandon Hughes in the opener role. On Tuesday, it was Joe Mantiply. Both allowed hits to Ohtani but got two outs in the first before giving way to Nelson.

Behind Hughes, Nelson hurled five scoreless frames as Arizona won, 6-0. Behind Mantiply, Nelson was solid again, allowing the inherited runner to score but delivering five innings once again, with one earned run. The effort matched his career high in relief innings, and marked the third time in his career tossing 4 2/3-plus relief innings while allowing one earned run or fewer.

It was a nice rebound for Nelson, who showed flashes of his potential in June with three quality starts, but also endured two outings in which he couldn’t escape the fourth inning, including his most recent game.

"We've just been trying to try to calm down the leg kick a little bit and try to allow myself to get out in front easier,” said Nelson. "And I think the last start, I was getting a little bit too far down the mound and not really able to get out in front of everything, which just helps the slider, changeup and even the fastball location, too."

A big difference between that game in May and Tuesday is that, with Hughes optioned to Triple-A Reno on Saturday for the third time this season, the D-backs are currently operating with just one lefty in the bullpen. That meant that if the score was close and Ohtani and Freeman were due up late in the game, there would be no left-handed specialist available for them.

Lovullo and his staff weighed the possibilities, ultimately deciding that they’d rather use Mantiply for a guaranteed matchup against both Ohtani and Freeman, rather than save him for a hypothetical one that might not arise.

That situation did arise on Tuesday late in the game, though Lovullo said that he wouldn’t have gone to Mantiply with a one-run lead in the ninth. And things started off well for Sewald, who struck out Gavin Lux and Ohtani to get Arizona within one out of a win.

But Sewald threw a middle-high four-seamer to Will Smith, who doubled off the center-field wall to give the Dodgers some life. There was talk of intentionally walking Freeman, but the D-backs opted to let Sewald face him.

Sewald got Freeman in an 0-2 hole before the Dodgers’ first baseman connected with a fastball on the outer edge of the plate for a game-tying double to right.

"Any time I've ever gotten Freddie out were pitches that were right down the middle, and the only time he gets hits are really good pitches,” said Sewald. “... I don't know how he does it. His bat, it just doesn't really make any sense physically how he can get the barrel to anything, and he manages to get the barrel to everything."

Two pitches later, Teoscar Hernández grounded a middle-middle heater to left field, bringing in Freeman and ending the game.

It was a tough loss for the D-backs, who’d had their share of momentum swings in the back-of-forth affair. Christian Walker hit a two-run blast in the fourth, his 15th homer in his 40th career game at Dodger Stadium. An errant throw on Jake McCarthy’s pinch-hit bunt tied the game in the eighth. Arizona had just taken the lead in the top of the ninth on a Joc Pederson homer that landed in the seats just inside of the right-field foul pole.

"Whoever watched this game tonight saw a team that was just very eager to go out and do anything they could win a game,” said Lovullo. “And we were one strike away from from a win. But moral victories don't count in this game. We've got to go out and find a way to get it done tomorrow."