OAKLAND -- Ahead of the 2023 campaign, if you had to pick one Braves pitcher to lead all qualified starters in ERA through the first two months of the season, it probably wouldn't have been Bryce Elder.

But with one day remaining in May, Elder sits atop the Major League leaderboard after lowering his ERA to 1.92 with another commanding performance in the Braves' 2-1 walk-off loss to the A's on Tuesday night at the Coliseum.

"He's been unbelievable for us," Austin Riley said. "[To] only put up one for him, that doesn't sit very well. He's been great. All you can ask for."

For what it's worth, Elder isn't celebrating his early success just yet. His eyes are trained toward improving on a promising beginning to the year.

"I think I've got a pretty good way to go," Elder said. "I think I could still get better. I think I've been making pitches. … I'm 11 starts in, and in a full year, you make about 30 to 35. That's not quite a third, so we've got a long way to go."

The Braves right-hander recorded an out in the eighth inning for the first time this season, allowing one run on five hits. Elder struck out five and wasn't overly pleased with his command after issuing three walks.

Atlanta saw a lot of success with Elder on the bump this month, winning four of his six outings. Elder recorded four quality starts and allowed just seven earned runs over 36 2/3 innings.

On Tuesday night, neither Elder nor his team was rewarded for his latest strong effort on the mound.

"It's tough," manager Brian Snitker said. "He had a great start. [A.J. Minter] came in, did a really good job. [Raisel Iglesias] didn't have it. We didn't score enough runs, obviously. We've just got to get the bats going again."

Entering the game, the Braves led the National League with a .942 OPS against lefties, but they managed only four hits against A's southpaw JP Sears. One of those knocks accounted for Atlanta's lone run of the game on Kevin Pillar's solo homer that banged off the left-field foul pole to lead off the third inning.

In a game defined by stingy pitching on both sides, mistakes that would normally be minor were magnified. That was the case in the bottom of the ninth inning, when Iglesias entered with the game tied, 1-1, and recorded only one out, walking three batters. Iglesias had issued two free passes across nine prior outings this season.

"It's extremely frustrating," Iglesias said in Spanish through team interpreter Franco Garcia. "It's no secret that I throw strikes. I'm not one of those pitchers who throws balls regularly, so for me it was really challenging not being able to find the strike zone."

That loaded the bases for A's third baseman Jonah Bride, who hit a grounder to Riley that could have resulted in an inning-ending double play. Instead, Riley bobbled the ball and made a late throw to the plate, sealing Oakland's walk-off victory.

The Braves had not lost a series to the A's since 2005, which was the second year the clubs met in Interleague play. With a short turnaround to Wednesday's finale, they're determined not to linger on a frustrating evening.

"You're always trying to look at the positives in this game," Riley said, "because there are so many failures. Tonight was a tough one. Just try to clear your mind as quick as possible, got another one tomorrow, and come back and get ready for that one."