ATLANTA -- The Mets arrived in Atlanta for their biggest regular-season series in recent memory on Friday knowing they needed only one win this weekend to remain in control of their own path to an NL East crown.

They left on Sunday night knowing one more loss or Braves victory would seal their fate as an NL Wild Card team. The Mets (98-61) squandered an early lead and let a number of opportunities slip away -- a microcosm of the weekend, as a whole -- in a 5-3 loss to the Braves (100-59) on Sunday night at Truist Park.

The loss dropped New York to two games behind Atlanta in the NL East, though it's essentially 2 1/2 games since Sunday's contest also clinched the tiebreaker for the Braves, who finished 10-9 against the Mets this season.

Games remaining: 3 (at home vs. Nationals)
Standings: 2 games behind Braves in NL East
Tiebreaker info: Atlanta owns the tiebreaker by virtue of winning the head-to-head season series (10-9)
Magic number: 6

“They only won one more game against us during the [season] series, so it’s been back and forth,” Pete Alonso said. “It’s just two really good teams going back and forth in the division race, and this weekend, they just played better than us.”

The sweep means the Mets' only path to their first division title since 2015 is to sweep the Nationals this week at Citi Field and hope the Braves are swept by the Marlins in Miami.

“We'll see if we can make it still happen,” manager Buck Showalter said. “But we're going to need some help now, that's what's frustrating.”

“How many games are they up?” Alonso asked rhetorically. “They haven’t won the division yet.”

The Mets have spent 175 days in first place this season. They came into the weekend with a chance to clinch the division with a sweep. Yet the Braves, who will wake up Monday in first place for just the sixth day this season, flipped the script with a sweep of their own.

After losing games started by Jacob deGrom and Max Scherzer on Friday and Saturday, respectively, the Mets staked Chris Bassitt to a 3-1 lead in the top of the third inning on Sunday.

Neither the lead nor Bassitt lasted through the bottom of the third.

With two on and two out, Bassitt hit Austin Riley with a pitch to load the bases. He then walked Matt Olson to force in a run before giving up a go-ahead two-run single to Travis d'Arnaud that ended Bassitt's night after just 2 2/3 innings.

“We've had some slip-ups against them earlier in the year,” said Olson, who homered in all three games of the series. “And obviously when you see deGrom, Scherzer and Bassitt you know you’ve got to come with your A-game."

The trio of deGrom, Scherzer and Bassitt combined to allow 11 earned runs in 14 1/3 innings (6.91 ERA) in the series. Offensively, the Mets managed just seven runs in three games while stranding 22 baserunners.

“They just flat-out beat us this weekend,” Alonso said. “They played well. Good for them. Tip your cap.”

The Mets now return home to host the Nationals, with Carlos Carrasco slated to start on Monday and Taijuan Walker on Tuesday. deGrom would be in line to start Wednesday, but that seems unlikely after the way this weekend unfolded. Even if the division was still in question come Wednesday and deGrom started and led the Mets to a win, the Braves could still clinch by winning their finale in Miami. More importantly, starting Wednesday would take deGrom out of the equation to start in the NL Wild Card Series.

Things are much clearer if the Braves clinch the division on either Monday or Tuesday. New York would simply hold back deGrom to start one of the first two games of the NL Wild Card Series, alongside Scherzer.

“They're going to get a chance to roll the dice in October, regardless,” Showalter said. “ … If I know these guys, they'll rebound and look to make somebody feel their pain.”

There is still plenty to be decided over the next three days, from the NL East title to the Mets' potential postseason opponents to the way they line up their rotation. 

But there’s no question that all of it was made more difficult by leaving Atlanta without a win.

“I think we have a really good chance to do something really special,” Alonso said. “Obviously not the results that we wanted, but we’re still a really good team, we’re still going to the postseason and this is what it’s all for.”