SAN DIEGO – It would be easy to lay most of the blame for the Atlanta Braves’ 4-0 loss to the San Diego Padres in their Wild Card Series opener at the feet of AJ Smith-Shawver, who got a first pitch two gave up -run homer to the second batter he faced, Fernando Tatis Jr., on a pedestrian fastball over the middle of the plate.

Or to blame the Braves officials for their decision to start a 21-year-old rookie who had pitched just one Major League game this season – which was four months ago – and eight MLB games in his career, including one previous postseason appearance: in which he allowed three home runs in 2 2/3 relief innings.

But the game was not lost when Smith-Shawver retired with one out in the second inning on Tuesday evening with the Braves trailing 3-0. At least, it didn’t have to be that way. However, couple that with the way right-hander Michael King completely dominated Atlanta’s hitters with 12 strikeouts in seven innings, and yes, it was over.

So now the Braves, powered by players who did their best work this season when others wrote them off, are faced with a situation where their backs are against the proverbial wall. They need to win on Wednesday night in the sold-out cauldron that is Petco Park during the postseason or the Braves will be done until the spring.

“Here we go,” Braves catcher Travis d’Arnaud said of the message he will have for teammates. “It’s almost like (Monday): it’s win or go home. We all know what the situation is, and we will be ready to play.”

Travis d’Arnaud delivers a message to AJ Smith-Shawver during an eventful second inning. “He came ready to go. He was excited.” (Sean M. Haffey/Getty Images)

The Braves faced a must-win situation in the second game of Monday’s makeup doubleheader against the New York Mets after blowing a lead and losing Game 1, as the Mets were drawn a wild-card took place.

The Braves needed to win the second game that day to clinch a wild card spot, and they did, with Grant Holmes flourishing during an emergency start after Chris Sale was scratched due to back spasms. The bullpen also came through, including a pair of relievers, Joe Jiménez and Raisel Iglesias, who gave up big runs in the first game and came back undaunted in the nightcap.

The Braves will send Max Fried to the mound on Wednesday, and teammates say he’s the ideal man for the job. Adding more drama, it could be his last start for the Braves, as Fried is a pending free agent.

Do the Braves feel good about their chances of squaring the series and forcing a Game 3?

“Absolutely,” said Aaron Bummer, who threw 2 2/3 hitless and scoreless innings Tuesday on a night when he and two lower-leverage relievers, Jesse Chavez and Luke Jackson, allowed just one hit in the 6 2/3 innings after Smith. -Shawver left the game. That hit was an eighth-inning home run by Kyle Higashioka off Jackson.

The effort allowed the Braves to rest high-leverage pitchers who had worked heavily the previous two days, giving Atlanta a full-capacity bullpen behind Fried on Wednesday.

“(Fried) has gone out and done it, he’s pitched in the World Series, he’s done a lot of things,” Bummer said. “I’m excited to see him pitch, and I know he’s going to go out there and … he’s going to compete as best he can. I don’t want anyone else but Max right now.”

D’Arnaud said of the team’s thoughts on Fried pitching in the must-win game: “All the confidence in the world. He has played in big games like this. He steps up in big games like this, and there’s no one else we’d rather have on the mound.”

When the Padres heard that Sale, the NL Triple Crown winner and presumptive Cy Young winner, had been cut from Monday’s doubleheader, they wondered if he would pitch in the Wild Card Series. When he was no longer on the series list, they got their answer. They knew what it meant for the Braves.

“Chris Sale was probably the guy that, I think, the whole (Braves) team would want to pitch,” Padres shortstop Xander Bogaerts said. “But he wasn’t available, so you have to bring someone else up. Obviously we know the situation they were in. It was bad (for them), but it’s baseball, right?

Meanwhile, the Padres had their best lineup for the series, with Joe Musgrove against Fried on Wednesday and Dylan dropping out to start a potential Game 3 on Thursday. The Braves will likely start Reynaldo López in Game 3 if they can get there.

King made their path significantly more difficult in his first postseason start. By striking out a dozen batters without walking in seven innings while allowing just five hits, including four singles, King had one of the best first playoff starts in history.

It was the second-most strikeouts in a single game in Padres postseason history, behind Kevin Brown’s 16, and King was first in MLB history with 12 strikeouts and no runs or walks in a postseason game.

“He controlled the zone, he controlled the play,” Braves midfielder Michael Harris II said. “I think he struck out 12. That’s a lot of strikeouts. He definitely did a good job making his pitches and controlling the game.”

Padres reliever Jason Adam struck out three more Braves in the eighth inning, as the Padres became the first team in postseason history to strike out at least 15 batters in a game without allowing a walk or run. In fact, no other team’s pitchers had more than 11 strikeouts without walks or giving up runs in a postseason game.

“I think the biggest thing for us was not to miss the pitch we’re going to hit,” Harris said. “(King) did a good job of not leaving it in the middle of the board, so it was tough.”

The Braves looked for strikes and swung at many pitches well outside and inside the strike zone, swinging at sliders, sweepers and sinkers that were a foot or more from the plate.

“He located both of his (fastballs), in and out,” d’Arnaud said of King. “He sunk the back door, then came out and then four seams in, four seams out. Even his slider, he was able to throw it for a strike and make us chase it as well.

And Smith Shawver?

“He was ready to go, he was excited,” d’Arnaud said. “He looked good in the bullpen. Unfortunately, they were able to take advantage of some mistakes. Tatis got there early, the first pitch was ready to go, he got a pitch and he didn’t miss it. So you have to give those guys credit. To grab the ball there as a 21-year-old is impressive. He wasn’t scared, he just made a few mistakes and we had to pay for them.”

The Braves didn’t expect the usually harder-throwing Smith-Shawver to come out with 93-94 mph fastballs, which he did with the first two batters. Seven pitches in, he had allowed a single to NL batting champion Luis Arraez and a huge 110.8-mph, 400-foot homer to Tatis on a 90.5-mph fastball across the plate.

“Obviously it didn’t go the way you put it, but that’s baseball,” Smith-Shawver said. ‘Tatis likes it. I actually left one there.”

He threw just three fastballs above 95.8, and the 95.0 average of his 15 fastballs was 1.8 mph lower than what Smith-Shawver posted in his May start against the Cubs at Wrigley Field — an encouraging feat, but one that left him with a tense oblique. put him on the injured list.

“He started at 93,” said Braves manager Brian Snitker, who didn’t expect that from Smith-Shawver early Tuesday. “Then suddenly I saw 98s there. We have been successful in limiting the damage. And the bullpen did a great job of keeping the game there.

“Like I said, it wasn’t because of who we started that we didn’t win this game. We couldn’t get anything going offensively.”

Smith-Shawver was asked about his low velo on those early throws, including the one Tatis crushed.

“Just try to go out there, try to throw a few over the plate and settle in,” he said. “And whenever you want, you can step on it. That’s pretty much what I did this year. A bit of back and forth.”

But this isn’t Triple A. This is a best-of-three MLB postseason series. The need to ‘get on it’ was immediate.

And now the Braves and Fried have no room for error. It’s win or go home.

Fried said before the game that he had not had a chance to talk to Smith-Shawver since he was named to start the game because the rookie had not been notified by Snitker until just before noon Tuesday. But if he had a chance to talk to him, Fried said he would have said, “Go outside and leave it all out there.” Don’t regret it.”

That didn’t happen on Tuesday. Now Fried and the Braves, including and perhaps especially their hitters, have to do it on Wednesday.

(Top photo of Marcell Ozuna: Sean M. Haffey / Getty Images)