A casual fan’s guide to Atlanta United’s MLS Cup playoff

On Sunday, Atlanta United faces off against New York City FC at Yankee Stadium in the first round of the 2021 Major League Soccer playoffs.

Why it matters: Atlanta United won its first (and thus far only) MLS Cup in 2018, but sat out last year's tournament.

• If you don’t follow the team, don’t worry, we’re here to help, with the help of our friends.

Who to watch: On the Atlanta side, it’s Santiago Sosa, a defensive midfielder who’s been out since an injury since Oct. 20th — the last time the Five Stripes played the New York team.

• “Atlanta has felt his absence keenly in recent weeks,” Payson Schwin, a Dirty South Soccer contributor, tells Axios. “Sosa will need to step up big to support his backline as they cope with a potent NYCFC attack that features MLS MVP candidate Valentín ‘Taty’ Castellanos.”

Don't forget Josef Martinez, Jillian Sakovits, an MLS and Atlanta United host and sideline reporter, tells Axios.

• The 2018 MLS MVP is coming off a golazo against FC Cincinnati that secured Atlanta United a playoff spot. "Josef during the playoffs is a whole other beast," Sakovits says. "I am eager to see what [Martinez] has in store after he and his team missed the 2020 playoffs completely."

Know their weak spots: Key NYCFC defensive players are out due to injuries.

• Atlanta must contain Castellanos and midfielder Maxi Moralez, says Jason Longshore, an Atlanta United commentator and host of Soccer Down Here. If they do so, "[the team] will absolutely have opportunities to get at the NYC defense."

New terrain: Yankee Stadium is a unique venue. "Needless to say, soccer wasn't meant to be played there," Sydney Hunte, a Dirty South Soccer contributor, tells Axios. "[B]ut on NYCFC's end it's been able to use that to its advantage."

Know your tunes: Fan groups Terminus Legion and Resurgence have a handy round-up of supporter chants.

Who to follow: In addition to the sources above, check out Felipe Cardenas, Doug Roberson, Rob Usry, among many others.

What’s next: The fun starts at 3pm on ABC and ESPN Deportes.