2. The 2010 US Open Cup
Sure, anyone can win an unlikely trophy in their first year of competition, but surely it's impossible to do it twice in a row?
Apparently not! Another 2-1 win in a final, this time against Columbus Crew, gave the Sounders an incredible second trophy in two seasons. Returning seven starters from the 2009 final, they got off to a tough start when Kevin Burns opened the scoring for the Crew within half an hour.
Sanna Nyassi hit back before half-time to pull Seattle level though, and scored again midway through the second period to take a lead which was never truly threatened – becoming the first player in 15 years to score multiple goals in the tournament's final.
3. The 2011 US Open Cup
Yes, really. Three years of competition, three US Open Cup wins. This one had the most comfortable scoreline – a 2-0 win over the Chicago Fire – but was perhaps the tightest match of the three.
A cup record crowd at CenturyLink Field watched at the match approached the final 15 minutes with nothing separating the two defensively-matched sides, although Seattle had hit the frame of the goal twice.
For the second time in three years though, Fredy Montero broke the deadlock when a saved header rebounded right to his feet in front of goal. Chicago spent the remainder of the game throwing everything at Keller in the Sounders goal, but that attacking nature left Osvaldo Alondo free to score a counter-attacking goal deep in injury time to seal the win.
4. The 2014 US Open Cup
A three-year gap between trophies was unheard of in Sounders history, but they did go close – only a penalty shootout defeat by Sporting KC in the 2012 final preventing a historic four-peat.
Seattle fans might've had the same concern in 2014 too, as Chad Barrett's goal for the Sounders cancelled out Maurice Edu's opener to take the 2014 final to overtime.
As it happened, they needn't have worried. Clint Dempsey, in his first full season for the club, scored the go-ahead goal in the 101st minute before fellow Premier League veteran and designated player Obafemi Martins made sure of the win with a handful of minutes left.
But a new trophy was about to enter the Seattle cabinet...