Darlington Nagbe - Portland Timbers - fends off - Wil Trapp - Columbus Crew SC

The 2015 season has come down to its final 90 minutes.

Columbus Crew SC and the Portland Timbers are set to duke it out in this year's MLS Cup at MAPFRE Stadium on Sunday (4 pm ET, ESPN | UniMás | TSN | RDS2), and there are plenty of storylines and subplots to consider as the countdown to kickoff cranks up.

Here's a few to get you started.

1. Porter vs. Berhalter

One coach is a widely respected wunderkind and considered one of the United States' most promising managers; the other, a former US national team mainstay whose top-to-bottom retooling of his club has dazzled observers close to home and far afield.

Timbers boss Caleb Porter probably gets more press than Columbus' laconic Gregg Berhalter. But the latter coach proved a similarly quick study in MLS, with Crew SC skyrocketing from eighth place to the summit of the Eastern Conference barely two years into his tenure.

Both gaffers have shown an eye for talent evaluation and impressive tactical chops. Each has overcome early setbacks in their pro careers: Porter helming the US U-23's ignominious 2012 Olympic qualifying debacle, and Berhalter earning an abrupt dismissal from his first head coaching job, Swedish club Hammarby IF. Now, they face off for the top prize in MLS.

2. Nagbe or Trapp?

USMNT fans constantly keep their eyes peeled for The Next Big Thing in American Soccer™, and two of the most influential midfielders in this matchup have had the label slapped on them in recent years.

After years of waiting to achieve full US citizenship, Timbers star Darlington Nagbe finally made his national team debut in early November, making a strong impression on coach Jurgen Klinsmann. The US coach called Nagbe "a great fit" and "a real nice option" as the Yanks wade into 2018 CONCACAF World Cup qualifying. Sterling work in both attack and defense has fueled Portland's MLS Cup run, especially after Porter's switch to a 4-3-3 down the stretch this season.

Wil Trapp offers a contrasting skill set, less spectacular but – for Crew SC – similarly crucial. A deep-lying center mid with a refined passing range and high soccer IQ despite relatively tender age (22), the Columbus Homegrown sets the tempo for their fluid, high-octane style. He has gotten a call from Klinsmann, but it's unclear exactly how Trapp figures into the current USMNT plans.

3. Can Kei come good?

After falling just short of the MLS Golden Boot – denied only by an otherworldly campaign from Sebastian Giovinco – Crew SC striker Kei Kamara is looking to cement a career year with a trophy.

The Sierra Leone-born star has approached the summit on more than one occasion in a well-traveled MLS career, but has been denied that glory, perhaps most painfully when his former Sporting KC teammates won the 2013 title – across the Atlantic; Kamara left SKC for English Championship side Middlesborough on a midseason transfer.

Kamara ended an extended playoff scoring drought with a goal in the Eastern Conference Semifinal against Montreal. Can he cap his great leap forward with an MLS Championship?

4. Meeting of Argentine maestros

Buenos Aires products Federico Higuain and Diego Valeri are the cultured playmakers who bring vision and rhythm to their respective attacks.

Though both can be considered traditional No. 10s, they go about their work in different ways: Higuain ranging all over the pitch to facilitate clever offense; Valeri powering through to wrest control of the action. Yet they share an incisive ability to inspire and enable their teammates' best qualities, and neither can truly be replaced when injury or suspension rules them out.

Sunday's game might well be decided by which one can reach greater heights under the hot spotlight.

5. Will Portland claim Cascadia bragging rights?

The soccer-mad cities of the Pacific Northwest have brought myriad, enormous benefits to Major League Soccer. Yet none of the Vancouver-Seattle-Portland trio have reached the league's showcase showdown – until now.

That alone serves as a valid source of pride in the Rose City, but will be rendered a historical footnote if they can't get the job done in Columbus. Becoming the first Cascadia side to claim an MLS Cup? That would vault PTFC to a status unmatched in the region's rich soccer history.

For fans, the fierce partisanship in that part of the world makes rivals' success nearly as painful as their own club's failures, so Sounders and Whitecaps supporters could find themselves donning Black and Gold for a day.