Who: Philadelphia Union vs. Seattle Sounders

What: 2014 US Open Cup Final

Where: PPL Park

When: 7:30 pm, Tuesday, Sept. 16

Watch: TCN, GolTV, KlowdTV

Whistle: Armando Villareal; Linesmen: Peter Manikowski, Corey Parker; Fourth Official: Matthew Nelson

Philadelphia Union and Seattle Sounders could not be more tactically different. The quality that unites them is a single-minded devotion to a system that the entire team understands. This system-guided philosophy can lead down the wrong path if the personnel don’t fit (see: Hackworth, John). But Jim Curtin and Sigi Schmidt have the right players.

And it starts in the middle of the park.

Talented twosomes

Even though Seattle puts an emphasis on all-out offense, contrasting Philadelphia’s shape-first-attack-second structure, the demands on the players patrolling the central areas are quite similar. Osvaldo Alonso and Gonzalo Pineda provide the stable core around which the many moving parts of the Sounders’ attacking thrusts revolve. When DeAndre Yedlin pushes up, the midfield rotates to provide cover. When Clint Dempsey, Obafemi Martins, and Lamar Neagle are all high up the field, the midfield presses higher to compact space.

Philadelphia can be just as dynamic as Seattle, but retains more defensive shape, with Sheanon Williams often the only defender rushing forward. Instead of pressing to close space, Amobi Okugo and Vincent Nogueira will slow play down and push it to wide areas while the team’s energetic wingers track back to re-form a bank of four behind Cristian Maidana. The twist in the Union’s game has recently come from the center, as Maurice Edu will glide into the opposing half with the ball while Okugo drops into defense.

Casino Curtin?

Since, as a general non-Messi rule, players move faster without the ball, the central midfielders on both teams must be talented two-way players for these systems to prosper. The Sounders feature one of the most consistent box-to-box players in MLS in Alonso, and his partnership with the intelligent Pineda has created the base of an offense that can push players high and expect them to receive the ball. Indeed, Seattle tends to gamble going forward precisely because they have such confidence in their holding duo to play the right pass.

Jim Curtin may coach in a riverfront stadium, but he is far from a riverboat gambler. The Union’s transition game is almost purely a counterattacking strategy. Instead of attacking with numbers, Philadelphia prefers to wait until the numbers favor them. A consistent feature of Union attacks is the wingers’ ability to pull central defenders high or to the flanks then connect a short pass or two to release Wenger or Le Toux into space. Cristian Maidana rightly garners high praise for his role in the transition game, but Conor Casey is also a key element. The big man spreads the field well and has learned to utilize the player in the hole — be it Maidana or Nogueira — when under pressure.

A perfect fit

Indeed, the most intriguing aspect of this final is how well the opponents appear to complement each other on paper. The Sounders are unworried by teams that sit deep since it allows them to push more players into attack. The Union welcome pressure, assuming that it leaves more gaps for the vaunted counter to exploit.

When two systems appear to play into each other’s hands so well, soccer tends to point its spotlight on special players. Clint Dempsey can do something special at almost any moment. But against a team so good at maintaining defensive shape in the face of movement, he or Martins will have to do something special. For the Union, the same must be said of Maidana and Nogueira. Both players have evidenced the ability to make highlight-reel passes. To get the best of a buzzing Seattle side, they will have to be special multiple times on Tuesday.

To change or not to change

The defense, that is.

Ethan White has been a constant in back during Philadelphia’s stunning script-flipping this season. And even though he gave up a dubious penalty on Saturday, the Maryland product can still make a strong case to start in the final.

But he won’t. White’s size and speed are huge assets, but they cannot always make up for the difference between how quickly he and Carlos Valdes read the game. Valdes and Maurice Edu are already one of the better defensive pairings in the league, with the potential to be the best. Their skill on the ball fits perfectly with Philly’s desire to break quickly out of defense with by pairing a long outlet pass with quick exchanges near midfield.

White has been good — not great, but good enough to make Union fans forget the tottering defense that characterized March through May — but Valdes and Edu are the beams around which a playoff house will be built going forward.

Even so…

Can any combination of Union defenders control the Sounders offense?

Absolutely. The key is, as it has always been, defensive shape. If the Union are beat by a 30-yard screamer, so be it. If Seattle is settling for long shots, Philly is doing their job. Because the Sounders are so good at breaking down defenses, that they rarely need to rely on the spectacular; their highlights are the passes and movement that lead up to goals.

The pressure will be heaped on Amobi Okugo in the middle. He is responsible for forcing the Sounders wide and tracking the late runs that Dempsey and Martins make with such intelligence and guile. Okugo’s defensive responsibilities may mean that Vincent Nogueira has to take the bulk of the distributing load. And that’s fine. He’s really quite good.

A home final is a special, special thing

Truly, the US Open Cup final could not be a better feature for Major League Soccer this season. Philadelphia brings a mix of drafted talented and designated players that has turned into one of the better tactically disciplined teams in the entire league in, oh, two and a half months. Seattle lugs in the big, showy names in Dempsey and Martins, and the almost-equally hyped Yedlin in back. Storylines abound.

Additionally, neither team arrived at this point by sitting back, defending, and nabbing a smash-n-grab goal. Even though Philly’s offense is built on a strong defensive structure, they have every intention of attacking off any turnover or loose ball. As many finals do, this one will likely start off cagey and open up as the teams shake off jitters and fall into a rhythm.

The biggest challenges for the Union will be avoiding early mistakes and maintaining a willingness to counterattack in an environment where the pressure can lead to hesitancy and conservative play.

The onus will be on the fans to wash away the home team’s anxiety with wave after wave of noise. PPL Park will be like it has never been before.

Philadelphia Union. At home. With ninety minutes between them and the cup.

Are you ready?