Those wondering why the Dodgers hesitated making the ninth inning off limits to Kenley Jansen saw the bullpen melt down without him in the ninth inning Monday night.

Blake Treinen allowed a monstrous tiebreaking homer to No. 9 hitter Austin Riley. Jake McGee allowed a two-run blast to Ozzie Albies. And the Dodgers, heavy favorites to win the World Series, lost Game 1 of the best-of-seven National League Championship Series to the Braves, 5-1, at Globe Life Field in Arlington, where fans were in the stands for the first time since Spring Training.

• Box score

Both teams entered this series unbeaten in the previous two series. Teams that have won Game 1 of the NLCS have gone on to win the series 35 of 50 times (70 percent), including six of the past seven years (the Dodgers lost Game 1 in 2018 at Milwaukee, then won in seven games).

So, as talented and versatile and balanced as the Dodgers are, and despite the fact they had the lowest bullpen ERA in the league, Atlanta erupted against the Dodgers’ most vulnerable weakness -- the lack of a closer -- as Jansen sat in the bullpen in the ninth and watched this game go up in flames.

With a velocity drop and a shaky outing in Game 2 of the NL Division Series, Jansen was demoted as closer. The ball in the ninth instead went to Treinen, former closer of the A’s, with the game tied and the Dodgers the home team, but that didn’t work either.

“I just felt in a tie ballgame right there, us the home team, that run [of batters, mostly right-handers except for Freddie Freeman] right there was really good for Blake,” said manager Dave Roberts. “He’s going to have to do it again. It just didn’t work out, but I trust he’s going to get those guys out.”

And McGee, making his first appearance since Sept. 25?

“Blake got to 20 pitches, they put up another run and I wanted Jake to get some work and he couldn’t get it far enough away from Albies and he put a good swing on it,” said Roberts.

While those two moves didn’t work, the first three relievers to pick up after starter Walker Buehler’s five-plus innings pitched like ninth-inning candidates. Brusdar Graterol inherited two on and no outs from Buehler in the sixth inning and put out the fire 1-2-3, but the inning-ending comebacker hit the palm of his pitching hand and Roberts said that’s why he wasn’t sent out for the seventh. Roberts said Graterol -- who dominates right-handed hitters but not so much lefties -- is expected to be available for Game 2.

Dustin May, expected to start later in the series, took over and cruised through the seventh, then left a bases-loaded jam with two outs in the eighth for Victor González, who escaped by striking out former Dodgers hero Charlie Culberson.

“It was great to see Victor come in in a huge spot and kept us in a position to win the baseball game,” Roberts said. “Punching out Culberson, you’ve got five of the six guys [right-handed], I really loved Blake taking down that inning.”

And then came the ninth. The Dodgers believe in the depth of their bullpen, which numbers 13 if you add in swingmen May, Julio Urías and Tony Gonsolin. But playing the match-up game only goes as far as your pitchers can execute. Late-inning confidence seems lacking not only in Jansen, but also in Joe Kelly and Pedro Báez.

And the bullpen even got a slight break when Buehler, nursing a pair of finger blisters, overcame a career-high five walks to pitch into the sixth inning, after lasting only four innings in each of his last four starts.

• LA 'pleased' with Buehler, but he wants more

Buehler struck out seven, the ninth consecutive postseason game he’s reached at least that many, tying Randy Johnson’s record. Instead, Buehler focused postgame on his steady issuance of walks, which now number 11 in 13 postseason innings.

“I’ve got to stop walking guys and get deeper into games,” he said. “I was happy to get a little bit deeper, but I have to do more.”

Buehler’s worst pitch of 100 was rocketed over the fence by Freeman, the second batter of the game.

“Can’t make mistakes like that in games like this,” Buehler said.

Kiké Hernández, who homered off lefty Max Fried for the Dodgers’ only run in his first start of this postseason, said Freeman set the tone. Other than the home run, the Dodgers didn’t have a runner in scoring position after the second inning and finished with four hits.

“Their energy was a little bit better than ours tonight,” he said. “They came right out of the gates. Freddie hit that ball really hard and after that it put us on our heels a little bit. We’ll throw this one away and come back tomorrow with a fresh mind and do what we do.”