Martins came off the bench in the 60th minute to replace Chad Barrett, scorer of Seattle’s equalizer early in the second half, and within a few minutes he and Dempsey began untangling Philly’s defensive shape. Yet not until the 11th minute of the first overtime did Martins break loose to slip a ball that Dempsey drilled low inside the near post. Martins scored the clincher himself in the second period by chasing a long ball Leo Gonzalez and speeding past Ray Gaddis to clip the ball past keeper Zac MacMath’s late challenge.
Both teams were coming off MLS action -- Seattle beat Real Salt Lake, 3-2, on Friday and Philly tied New York, 2-2, Saturday -- yet the players maintained a fairly high level of intensity and pace. Both head coaches had rested regulars in the league matches; the teams each took 19 shots and combined for 19 corner kicks.
A thunderous celebration broke out when Edu got in between two Sounders to head home Cristian Maidana’s free kick from the right flank late in the first half, but Seattle bounced right back into the match shortly after halftime when Philly failed to clear a corner kick. A skied clearance wasn’t challenged by MacMath and after Chad Marshall headed the ball at goal Barrett reacted quickest to bang it in.
Martins' entry into the match sparked the Seattle attack, yet both teams needed staunch defending and some help from the woodwork to escape regulation at 1-1. Seattle keeper Stefan Frei blocked a point-blank attempt by Pedro Ribeiro and survived a Victor Nogueira shot off the post; Marco Pappa rattled MacMath’s crossbar and the young keeper stretched to tip over a Martins shot from close range.
The Union, playing on one fewer day of rest, lost its defensive shape in extra time as Martins and Dempsey took command. A dribbling run by Martins carved open the back line sufficiently for him to play a short diagonal ball that Dempsey smacked home with a first-time, left-footed shot.
After the changeover and several high balls into the Seattle penalty area had been repelled by Marshall and his back-line mates, Evans lofted a long ball out of the back and Martins turned on the jets to leave Gaddis in the dust and MacMath lunging in vain.
By winning the Open Cup Seattle earns a spot in the 2015-16 Concacaf Champions League tournament, though that spot would open up if it also wins the Supporters’ Shield or the MLS Cup title.
Sept. 17 in Chester, Pa.
Philadelphia 1, Seattle 3 (OT). Goals: Edu (Maidana) 38; Barrett 47, Dempsey (Martins) 101, Martins (Gonzalez) 114.
Seattle –- Frei; Gonzalez, Scott, Marshall, Yedlin, Evans (Pineda, 94), Alonso, Rose, Neagle (Pappa, 74), Barrett (Martins, 60), Dempsey.
Philadelphia –- MacMath; Williams (Fred, 105), White, Valdes, Gaddis, Edu, Nogueira, Le Toux, Maidana, Casey (Ribeiro, 78), Wenger (Cruz, 81).
Referee: Armando Villarreal.