Seattle got the night's first chance, but Santos would prove far more lethal in the second match of their CONCACAF Champions League tie.
The Sounders traveled to Mexico with a 2-1 advantage from the first leg. They looked likely to widen the margin in the eighth minute when a corner kick led to two headed chances in front of goal. First, Alvaro Fernandez saw his point blank header saved, then Brad Evans' follow-up found the gloves of Santos keeper Oswaldo Sanchez.
At that promising early moment, Seattle fans couldn't have known what they were in for.
Santos Grab the Game by Its Throat
Christian Suarez was superb for Santos all evening. He began the night on the left and just after Seattle's big moment in the eighth minute, the ball ended up at Suarez' feet outside the Seattle area.
Suarez created space between three Seattle defenders and fired his shot in at the near post to open the night's scoring.
Santos won the ball from the ensuing kick off, and a beautiful ball in behind Seattle's central defense found forward Oribe Peralta Morones.
Despite having Seattle defender Jhon Kennedy Hurtado draped all over him, Peralta managed to turn with the ball and slip it past goalkeeper Michael Gspurning to extend Santos' lead.
Santos Take a Break, Seattle Take Advantage
For the rest of the first half, Santos' midfielders had trouble getting on the ball and their attack fizzled.
Seattle, by contrast, saw Mauro Rosales get involved in the proceedings. Things looked considerably brighter with the Argentinian creating danger as he pulled more centrally from his starting position out right.
In the 37th minute, Seattle pulled one back with what would turn out to be forward Fredy Montero's only significant contribution to the match.
Montero received the ball on the left and looped a nice cross to the back post. Fernandez drifted into a completely unmarked position and met the ball cleanly. Goal Seattle. And the game looked promising.
Then The Second Half Changed Things
Right from the beginning, Santos owned the second half. A minute in and midfielder Daniel Ludueña slipped a ball through the Seattle back-line that found Herculez Gomez waltzing free on goal. Gomez shot on the turn, sent it high and put the golden opportunity to waste.
But the American international (and former Sounder) Gomez would have plenty to say before the match was over.
Just a few minutes later, Seattle created a half-chance when Rosales got in free on goal. Santos' keeper got to the ball first and snuffed out the opportunity.
The Mexicans immediately countered down the left side. The break found Suarez who pulled his cross back to the middle and a trailing Gomez. The forward calmly side-footed his first goal of the night (and second of the tie) into the Sounders net.
The Rout Was On
Thanks to their razor sharp movement, the Santos forwards seemingly found it easy to get in behind the Seattle back four throughout the match. Seattle's left side was especially vulnerable, as center-back Hurtado and left-back Leonardo Arce Gonzalez were torched repeatedly.
Once Santos moved Suarez over to the right side, things got even uglier for Sounders fans.
In the 67th minute, Peralta received with Hurtado on his back just inside the Sounders half of the field. Peralta dropped the ball to his support and spun off the inexplicably stagnant defender into miles of space in behind.
The return ball sent the Santos forward flying toward goal with Seattle's right side defenders struggling to recover. As he neared goal, Peralta played a square ball into the path of Gomez who raked it into the net to tally his second of the evening.
Ten minutes later, Santos defender Jorge Estrada Manjarrez pushed forward down the right. Upon receiving the ball, he veered toward the inside as forward Suarez pulled out wide.
The defender addressed Estrada, he played Suarez in and Suarez smashed the ball past a helpless Gspurning and into the far corner of Seattle's goal.
The Sounders appeared to have well and truly given up by this point in the match. But Santos weren't finished just yet.
Five minutes later, a long diagonal ball from Ludueña split Seattle's defense open for a final time. Hurtado should have cut it out, but his slip set substitute Santos forward Carlos Ochoa free. Ochoa slotted home and the tie was put firmly to bed.
6-1 Santos. 7-3 on aggregate.
1. Santos' attacking trio
Suarez, Gomez and Peralta were outstanding all match long. Seattle had no answer for their movement, their pace or their creativity. Once they truly began rolling in the second half, the game's outcome was sealed.
2. Switching Suarez to the right
Santos manager Benjamín Galindo moved Suarez to the right side during the second half. The move paid off handsomely, as the tricky forward took full advantage of the weakness in the left side of Seattle's defense.
3. Mauro Rosales' first half
The Argentinian played the key role in bringing the Sounders into the game in the first half. The team's inability to involve him in the second half was a contributing factor in their demise.
1. The left side of Seattle's defense
Hurtado and Gonzalez were miserable for Seattle. Gonzalez couldn't deal with the trickery both on and off the ball of the Santos forwards. And Hurtado was directly at fault for three of Santos' goals.
2. Fredy Montero
While Santos' forwards were shining at one end, Fredy Montero was shrinking from the spotlight at the other. Sluggish all game long, by the end of the match Montero might as well have been watching from the stands.
Santos' 7-3 aggregate victory sends them through to the semi-finals where they'll face Toronto FC. The first leg will kick-off on March 26th.