Ronald Acuña Jr. welcomes his brother to Atlanta with savage Instagram story following Mets loss

There's a lot on the line as the New York Mets and Atlanta Braves face off at Truist Park this week. These two NL East rivals have a long and storied history of not liking each other very much — especially this time of year — and New York entered the opener of a massive three-game set on Tuesday clinging to a two-game lead over Atlanta in the NL Wild Card standings.

But the postseason picture isn't the only thing at stake here. There are also some family bragging rights, as injured Braves star Ronald Acuña Jr. finds himself opposite little brother and Mets infielder Luisangel Acuña for the first time in their Major League careers. New York acquired Luisangel Acuña from the Texas Rangers at last year's trade deadline, part of the return in the Max Scherzer deal. Injuries to Francisco Lindor and Jeff McNeil got him promoted to the big-league club back on Sept. 14, and all he's done since is hit, slashing .379/.400/.828 over his first nine MLB games.

Tuesday marked the younger Acuña's first trip to Atlanta, and his first game against his big brother as a professional. Things started off friendly enough, as the two met up before the game to swap jerseys and pose for photos.

But if you thought that camaraderie would last past first pitch, well, you probably haven't spent too much time around brothers.

Ronald Acuña Jr. can't resist ribbing his little brother

Ronald might not be able to take the field as he rehabs another ACL tear, but that didn't mean he couldn't poke a little fun at Luisangel anyway. After Braves center fielder Michael Harris II robbed Luisangel of a potential hit with a diving catch in the top of the fifth, Ronald made sure to let his little brother know where his allegiances truly lay.

As a younger brother myself, it's hard to not wince a little in recognition here — after all, poking fun is just how big brothers let you know they love you. As for who will get the last laugh, however, that remains to be seen: Ronald's Braves drew first blood with a big 5-1 win on Tuesday night, narrowing the gap to just one game behind New York and a half-game behind the Arizona Diamondbacks in the race for the final two Wild Card spots. (The San Diego Padres have already punched their ticket to the playoffs, although they could still catch the Los Angeles Dodgers for the NL West crown with a hot final week.)

Luisangel will look to exact a little revenge on Wednesday night, as the Mets send lefty David Peterson to the mound against NL Cy Young favorite Chris Sale.