A give-and-go between two explosive offensive players eventually put a dagger in the Union's impressive run in the U.S. Open Cup.

Clint Dempsey converted a feed from Obafemi Martins in the 101st minute Tuesday night to break a 1-1 tie as the Seattle Sounders earned a 3-1 win in extra time in the U.S. Open Cup final at PPL Park.

Seattle won its fourth Open Cup title, all since 2009. The Union were trying to win the first championship in their five-year existence.

"I have never been proud of anything in my life that ended in a loss before, but this is the first time," said the Union's interim coach, Jim Curtin.

The Open Cup is open to all affiliated amateur and professional teams in the United States.

Dempsey took a pass inside midfield and found Martins, who returned the pass to his teammate. A three-time U.S. World Cup participant, Dempsey shot from the center of the box inside the near post.

That silenced the crowd of 15,256 except for the Sounders faithful who made the trip.

Martins gave the Sounders a cushion by scoring in the 113th minute.

The championship was highly contested, with nonstop, end-to-end action.

Union midfielder Maurice Edu connected on a header off a Cristian Maidana free kick to open the scoring in the 38th minute.

Maidana was about 15 yards outside the box on the right side, and his left-footed service was perfectly placed. Edu, standing inside the 6-yard line, beat Seattle defender Zach Scott on the header, and keeper Stefan Frei had no chance.

Seattle had the best early chance when Dempsey fired an Andy Rose cross over the crossbar in the 11th minute.

Before scoring, the Union's best chance came in the 30th minute, when Andrew Wenger fed Sebastien Le Toux, who was stopped in front of the goal by Frei.

Seattle earned the equalizer when the Union were unable to clear the ball following a Sounders corner.

Union defender Carlos Valdes headed the ball straight up, and Sounders defender Chad Marshall headed the ball toward the goal. Union keeper Zac MacMath deflected a shot in traffic in front of the goal, but Sounders forward Chad Barrett headed in the rebound in the 47th minute.

In the 76th minute, a sliding Dempsey just missed getting his foot on a ball that traveled past the far post. Shortly after, Martins shot wide from inside the box.

Union forward Pedro Ribeiro sent a close-range shot right at Frei in the 88th minute.

"I could have shot the ball harder, but if I shot too hard I thought it would go over," Ribeiro said.

An even better chance came during second-half stoppage time. After a give-and-go with Maidana, Vincent Nogueira hit the left post on a volley.

"We had the two chances at the end [of regulation] to win it, and I guess it wasn't meant to be," Curtin said.

In the first overtime, MacMath made a sensational one-handed deflection of a Martins shot from in front in the 93d minute.

During the second overtime in the 110th minute, Valdes' header from in front went right to Frei.