The "situation" of Sunday's loss didn't change until Tesho Akindele's 84th minute goal, but the "state" of the game undeniably shifted at half:
We've looked at this game progression chart on a few prior occasions (here, and here, for examples) - team stats are broken down into 10-minute sliding windows collected at 5 minute increments (e.g., 1st through the 10th minute, with a value shown at minute 5, or the 56th through the 65th with a value shown at minute 60)."Clearance bias" is simply the proportion of clearances to total defensive actions (attempted tackles, interceptions, clearances, and blocks), a metric I've used before to describe changes in defensive posture. A team with few upfield outlets under sustained attacking pressure will seek to clear its lines rather than attain possession. The numbers may be strongly influenced by general tactics (e.g. an emphasis on wide play will lead to many crosses and consequently many headed clearances from a solid defense), but within-game changes tend to reflect pretty clear shifts in play.
Seattle came out with strong defensive emphasis from two central midfielders and a concerted effort to avoid isolating either Fabian Castillo or Michael Barrios against any member of the backline. The posture forced long service reflected in a high long-pass/short-pass ratio that had, in 2015, been a fairly strong sign of poor play. For the first half, the posture worked... more or less. The Sounders had probably the better chances, a shot number advantage and in the end played a tough Dallas team with a home advantage to an even score at the break, holding onto the one-goal advantage from the first leg.
But what worked in the first half began to quite clearly fail in the second. Seattle stopped shooting, and service became still more direct. Dallas tripled its chance creation rate. Seattle defenders prioritized escape over possession and retained that posture until their opponents finally (almost-inevitably) opened the scoring.
The Sounders gambled on preventing that goal, sacrificing the offensive possibilities they had shown early on. I call it playing for a "pyrrhic" draw, because the team essentially conceded every other on-field contest (possession, chances, tactical initiative) in the effort to make Dallas' effort just weak enough, despite the risk of finding themselves chasing a goal with little time left (amazingly, Marco Pappa and Chad Marshall - my personal choice for Seattle's playoff MVP - found that goal anyway). Relying for 45 minutes on a failing tactic was a bad gamble.
Sigi Schmid did not have any particularly clear alternatives. Trusted defensive help was missing from the bench, and shifting the midfield toward possession (say, by substituting in Pappa and Gonzalo Pineda) may have had defensive drawbacks (and may not have worked regardless... when Pappa finally made it into the game, he struggled to adjust to passing targets who had clearly run out of gas long before). Holding off Dallas in the face of injury, exhaustion, and poor play from key players was a rough challenge to meet... but holding to a failing tactic for 40 minutes is more than worthy of criticism.
Raw data for this work was collected from OPTA via whoscored.com.