FC Dallas at Seattle Sounders on Monday night was just what the doctor ordered after a weekend of relative blowouts in the other three MLS Playoff Conference Semifinals. If 0-0 draws can be considered classics, the Dallas and Sounders clash surely must qualify with its frantic pace, controversial calls (or non-calls depending on who you ask), and almost-goals.

Despite winning the Supporter’s Shield, it was by no means a done deal that Seattle would edge out FC Dallas (despite the foregone conclusion Alexi Lalas and Taylor Twellman seemed to have already made during ESPN’s broadcast of Sunday night’s other Western Conference semifinal between LA Galaxy and Real Salt Lake). Seattle and Dallas drew 1-1 in the first Conference semifinal leg in Frisco a week ago. Thanks to MLS’ new away goal rule, the onus was on Dallas to score at least one goal in the return leg in Seattle, or face elimination.

Analyzing the lineups, FC Dallas had the bigger potential game-changer (who didn’t play in the first playoff leg) in Mauro Diaz, their diminutive Argentine midfielder who missed nearly half the regular season to injuries, then had to miss the first leg due to suspension for angrily protesting a referee decision late in Dallas’ elimination playoff win over Vancouver Whitecaps. When healthy, Diaz has proved an offensive maestro for Dallas, conducting final third attacks with neat angled passes and precise footwork. When Diaz is in the starting lineup, this allows Castillo to roam the flanks more freely, and a freely-roaming Castillo is – according to NBCSN’s Kyle Martino and several anonymous MLS defenders who spoke with him – the fastest player in MLS with the ball at his feet.

Seattle’s plan to deal with Diaz was essentially to crumple him to the turf, which they did early, often, and quite effectively. Diaz couldn’t establish the foothold he’s accustomed to in this match and Dallas suffered accordingly. Dallas held a slight advantage in overall possession in the match, but Seattle countered efficiently with Clint Dempsey and Obafemi Martins frequent menaces with the ball in the box. Anchored by team captain (and surely future U.S. Men’s National Team member) Matt Hedges, FC Dallas’ back line was reliably stingy, but goalkeeper Chris Seitz ultimately kept his team in the match with two huge saves (one in each half) in one-on-one showdowns with Clint Dempsey.

FC Dallas’ energy petered out around the 60 minute mark, and Seattle, despite not needing to score, pressed to put the match out of reach. FC Dallas fans undoubtedly grew impatient and frustrated with their popular coach Oscar Pareja for not taking advantage of any substitutes. Mysteriously, Pareja didn’t make any changes until the 80th minute, finally sending forward Andres Escobar on for Blas Perez. Seattle on the other hand, had to replace their utilitarian midfielder Osvaldo Alonso in the 56th minute when he went down with an apparent hamstring injury. It will be a big loss for Seattle if Alonso is unavailable for the Conference final against the Galaxy.

The back and forth, physical, pulsating match ended with a flurry of last gasp attacks from FC Dallas which yielded no major threats to Seattle’s goal. In the end, the Sounders escaped to keep alive their hopes of an unprecedented American treble (U.S. Open Cup, Supporter’s Shield and MLS Cup). Compared to their Conference final opponent LA Galaxy, however, the Sounders are back in to the final four, looking considerably less potent in attack than they did in late summer.

As for FC Dallas, they have to consider their 2014 playoff performance a triumph, considering they hadn’t made the playoffs since 2011. They proved they are a team to watch, with considerable youth (they have the youngest squad among all teams that made the MLS playoffs) and their homegrown players playing more minutes than any other team in the league this year. Oscar Pareja definitely has this team headed in the right direction, but tonight Seattle did just enough to end FC Dallas’ season.