Lionel Messi, Inter Miami will play the Philadelphia Union on Tuesday

What once seemed all but an impossibility is now a reality. Lionel Messi, arguably the greatest soccer player to have ever lived, will line up and play against the Union at Subaru Park.

That landmark moment arrives Tuesday, when the Union will host Messi and his new team, Inter Miami, in the Leagues Cup semifinals. The matchup was confirmed late Friday night with wins by the Union over Mexico’s Querétaro, and Inter Miami against Charlotte FC. While Inter Miami cruised to a 4-0 victory, the Union left it late, Chris Donovan scoring in the 10th minute of stoppage time to give the Union a 2-1 lead and send Subaru Park into a frenzy.

Messi, 36, announced he would be moving to Major League Soccer and joining Inter Miami on June 7, leaving French club Paris Saint-Germain and turning down lucrative offers from Saudi Arabia in the process. It was understood that Messi would not play for Inter Miami until July — after the Union’s two scheduled matchups with the Herons — so it looked as if local soccer fans would have to wait until next season to see the Argentine superstar up close.

» READ MORE: Lionel Messi picks Inter Miami, giving Major League Soccer its biggest superstar ever

The two glimmers of hope were that the Union could draw Inter Miami in the MLS playoffs or the Leagues Cup. With Inter Miami 12 points out of a playoff spot with 12 games to play, the Leagues Cup always seemed the likelier avenue, although those odds were minuscule in their own right. But the 47-team intercontinental tournament contested between MLS and Mexico’s Liga MX has played out perfectly, setting up a a dream semifinal matchup in Chester.

What are the Union facing in Messi, well how about the best player of his generation, and maybe the best ever (sorry Pelé). He is all but assured of winning his eighth Ballon d’Or this year (no other player has more than five), having led Argentina to World Cup glory last summer, previously the one major hole in his G.O.A.T. resume. Despite being 36, Messi is still arguably the best player in the world, and as he has shown in his brief stint in North America so far, he is still close to the top of his game.

Since arriving at Inter Miami for a record $50-plus million and other add-ons, including a share of MLS and Apple’s streaming deal, Messi has surpassed even his own lofty expectations. In 5 games, the maestro has fired in eight goals and also notched an assist, scoring two dramatic free kicks — one to beat Cruz Azul and one to force penalties against FC Dallas — to help the Herons reach the semifinals of the Leagues Cup.

Messi mania has swept the country and fans, including celebrities like LeBron James, Kim Kardashian, Tom Brady, and Diddy, have showed up in droves to see him. The results have been nearly sell out crowds and insanely high ticket prices — the few tickets Miami hasn’t sold out in the three games can be attributed to the prices. Tickets for his debut on July 21 were going for as much as $110,000.

But what should you expect at Subaru Park? Here’s everything to know ahead of Messi’s arrival in Philadelphia.

When does Messi play at Subaru Park?

The Union will face Messi and Inter Miami Tuesday at Subaru Park in the semifinals of the Leagues Cup. The time of the game is still TBD.

How did the Union and Inter Miami get here?

The Union cruised through group play with a pair of wins over Liga MX opposition. They defeated a nine-man Tijuana, 3-1, in their opener before the aforementioned thrashing of Querétaro. Things were much tighter in the round of 32, as the Union outlasted D.C. United, 5-4, on penalties after an 0-0 draw. Next came a date with the rival Red Bulls, with the Union winning again on penalty kicks following a 1-1 score after 90 minutes. There was more drama Friday night, as the Union needed Donovan’s stoppage-time winner to secure the matchup with Messi and Inter Miami.

Inter Miami’s somewhat improbable run to the semis of the Leagues Cup has included its fair share of Messi heroics. In his club debut, Messi came off the bench to fire an inch-perfect free kick into the roof of the net for a 94th-minute winner against Cruz Azul in a 2-1 victory. He topped that four days later with two goals and an assist in a 4-0 demolition of Atlanta United before bagging two more in the round of 32 in a 3-1 win over Orlando City.

But the Messi magic looked to have run out in the round of 16, as FC Dallas led Inter Miami, 4-2, with just 10 minutes to play. That’s when the 36-year-old clicked into gear with two free kicks. The first produced a catastrophic own goal from FC Dallas’ Marco Farfan; the second was almost a mirror image of his debut strike, a masterful curling free kick into the top corner. Inter Miami went on to win, 5-3, on penalties with Messi of all people slotting home the first of five successful kicks for the Herons. Messi scored for the fifth-straight game Friday as Inter Miami cruised to a 4-0 victory on home soil.

How to get tickets to see Messi

Tickets can be purchased from the Union’s official site. The club has not yet announced when tickets will go on sale.

Where can you watch Messi on TV?

In short, you can’t. Every Leagues Cup game is part of MLS’ massive “Season Pass” streaming deal with Apple. The subscription is $14.99 a month and can be accessed here.

Can the Union actually beat Messi and Inter Miami?

That remains to be seen, although the Union are a far more balanced team, at least they were before Messi’s arrival. The Union are 12 spots and 22 points ahead of Inter Miami in the standings led by goalkeeper Andre Blake, All-Star midfielder José Andrés Martínez, and attackers Dániel Gazdag and Julián Carranza. The game will be an especially big one for Carranza and midfielder Joaquín Torres, who both hail from Argentina. But Inter Miami are a totally different team with Messi — the Herons are 5-0 since his arrival — as well as fellow former European stars Sergio Busquets and Jordi Alba, who both also joined the team last month.

The Union lost 2-0 to Inter Miami in March before avenging that defeat with a 4-1 thrashing of the Herons at Subaru Park in June.