Updated

Chester, PA (SportsNetwork.com) - Seattle Sounders FC captured a fourth U.S. Open Cup crown in six years on Tuesday as Clint Dempsey and Obafemi Martins scored in extra time to hand Seattle a 3-1 win in the final over the Philadelphia Union at PPL Park.

Maurice Edu's 38th-minute goal put the Union in front as the club was attempting to win its first major trophy.

However, Chad Barrett equalized early in the second half to send the match into extra time, and Dempsey and Martins each found the net to help the Sounders clinch another title.

Dempsey squandered a great chance after 10 minutes when he fired a shot over the net from six yards after a good set up by Andy Rose.

Philadelphia took advantage and grabbed the lead before halftime with Cristian Maidana driving a right-wing free kick to the back post for Edu to turn past goalkeeper Stefan Frei with his head.

Seattle answered back with a set piece of its own in the 47th as Barrett headed home a close-range effort after the Union's Vincent Nogueira blocked an attempt on the goal line.

The home side had two great chances in the closing minutes to snatch the win as substitute Pedro Ribeiro had a deflected shot fall to him in the 89th minute inside the penalty area, leaving Frei out of position. However, Ribeiro shot the ball straight back into Frei as he scrambled to get back into the net, allowing the Seattle netminder to make the save.

The next chance came one minute later when Nogueira was played into the area by a nice chip but saw his right-footed shot come back off the post.

After escaping that late surge, Seattle grabbed the lead in the 101st minute when Dempsey exchanged passes with Martins and drove the return ball inside the left post from 14 yards.

Marco Pappa smacked a shot off the crossbar for Seattle as the Sounders attempted to extend their lead, but Martins sealed the win six minutes from time.

With Philadelphia pushing men forward, Martins found room to run at a defender and get into the area before slotting a shot past onrushing goalkeeper Zac MacMath to clinch the victory.