The former Fulham and Tottenham star was making his home debut in front of a franchise record crowd of 67,385 and was absolutely delighted he was able to be part of a victory in such a frantic meeting which was settled by Eddie Johnson's 60th minute goal.
"It's physical, it's reckless challenges, it's getting frustrated, it's battling through it, showing character - that's what you have to have in these types of games," Dempsey said.
"I thought the team showed a lot of character, kept the clean sheet, and Eddie does what he does. He comes up in big moments."
He added: "It's always going to be like that in derby games, when you're playing against your rivals. Everybody is going to show that they came to play, and at the end of the game I thought we had more quality and we deserved to win."
The victory allowed the Sounders to move into fifth place on the Western Conference table, just two points behind fourth-placed Portland, but with two games in hand.