The home side started the game well and Djalo came close to finding the net as he drilled a shot at goal from distance, but his effort went inches wide of the post.
The Sounders were beginning to grow into the game and Gonzalo Pineda nearly broke the deadlock when he weaved his way through two defenders and curled an effort at goal, which went just wide.
However, just before half time, Djalo handed the Earthquakes the lead when he latched onto Chris Wondolowski's pinpoint ball over the top of the defence and poked his shot through the legs of Stefan Frei.
In the second half, Djalo came close to doubling his side's advantage when his cross from the right nearly caught Frei off guard, with the keeper forced to scramble to beat the ball away from goal. From the rebound, Atiba Harris blasted his effort over the bar as he lost his composure at the vital moment.
Djalo was causing the visitors all sorts of problems and he should have given his side a two-goal cushion when Wondolowski released him on goal again, but this time he guided his shot wide.
The Sounders made one late push to find an equaliser as Pineda's corner found the head of Chad Barrett, but Wondolowski was on the line to stop a certain goal as he cleared the ball to safety.