Portland Timbers, Seattle Sounders set to play for 100th time Sunday

Perhaps the United States' most intense and historic derby will mark its 100th fixture in all competitions when the Seattle Sounders and Portland Timbers convene Sunday at Providence Park (4 pm ET | ESPN - full TV & streaming info) in the first of three regular season meetings in 2018.

It's a history that stretches back 43 years to when both were members of the NASL, and one that also includes multiple meetings in A-League, USL and U.S. Open Cup play. Here's a further breakdown:

Timbers vs Sounders 1975-Present

MLS regular season (2011-present) 5 9 6
MLS postseason (2011-present) 2 0 0
U.S. Open Cup (2005-present)
2010: SEA penalty kick win
2 4 1
USL regular season (2005-08) 4 6 4
USL postseason (2005) 0 2 0
A-League regular season (2001-04) 7 10 1
A-League postseason (2004) 1 1 0
NASL regular season (1975-82)
POR: 1 shootout win; SEA: 2 shootout wins
7 13 0
NASL postseason (1975) 1 0 0
Other league competition (1985-90) 6 5 2
TOTAL: 99 GAMES 35 50 14

On the MLS level, the sides will meet for a 23rd time in regular- or post-season play. The Sounders have a slim 9-7-6 advantage in those fixtures, though it was the Timbers who won both legs of their 2013 Western Conference Semifinal series.

This time around, both find themselves on the wrong side of the playoff line entering Week 11, but also entering on the heels of promising results; The Timbers are winners of three straight, while the Sounders pulled off a bit of a shock victory in their MLS Cup rematch at Toronto FC in midweek.

If that doesn't ratchet up the pressure enough, there's the latest offerings from each club's video production department. The Timbers have built upon the theme of last season's Fading Star mockumentary aimed at the LA Galaxy with "The Rivalry," a Ken Burns-inspired satire of the two clubs' history. Meanwhile, the folks at the Sounders spoke with players who were there for the inaugural match between the clubs in 1975, a 1-0 Seattle victory.

Just what will happen in the centennial chapter? Tune in Sunday to find out.