The Americans had only a handful of seconds left to run out the clock and advance a step closer to the Olympics. With the pressure building with each tick, victory slipped away. Right off their hands. The United States, known for producing top goalkeepers such as Brad Friedel, Kasey Keller and Tim Howard, found themselves done in Monday night when substitute Sean Johnson couldn't handle a long shot from Jaime Alas of El Salvador in stoppage time. The ball bounced off his hands, up over him and into the net, and El Salvador ousted the United States from Olympic qualifying with a 3-3 tie. "This is probably the worst feeling I've ever felt in my life so far as a pro athlete," U.S. captain Freddy Adu said. "This is going to be hard to get over. But at the end of the day things like this happen. For me, I never want to feel this way again, and I'm going to do whatever it takes to never feel this way again." The Americans had to win to reach Saturday's semifinals in Kansas City, Kan., and they led 3-2 on Joe Corona's goal in the 68th minute. Officials added 4 minutes of stoppage time onto the game, and U.S. coach Caleb Porter said they were "seconds away" from closing out the win and taking the top spot in Group A. A television clock showed the ball going in 4 minutes, 14 seconds into stoppage time. What happened is something U.S. midfielder Mix Diskerud said no one wants to experience in life, something he couldn't believe. "The last 20 minutes after our third goal, all those minutes felt like very, very long hours. But I thought we were going to make it. Everybody thought we were going to make it.," Diskerud said. "One shot." Alas stunned the Americans, who missed the Olympics for the second time since 1976 and second time in three Games. Several Americans dropped to the field in exhaustion and disbelief after the score, and Porter had to try to rally them back to their feet for one last gasp chance that didn't materialize. Porter said he hugged Johnson after the game. The 6-foot-4 keeper did not speak with reporters. "He feels like he's let everybody down, let his teammates down, and I told him he didn't," Porter said. El Salvador reached the semifinals, putting it a win away from its first Olympic berth since 1968. Canada, which tied Cuba 1-1 earlier, finished second. Lester Blanco and Andres Flores also scored for El Salvador, a team coach Mauricio Alfaro pointed out had less than two weeks to prepare for this tournament and didn't have the whole roster together until late. "It was just incredible," Alfaro said of the win through an interpreter. But Alfaro also said he had told his players to shoot more in the second half to try to pressure Johnson and the El Salvadoran coach said he did feel Johnson made a mistake on Alas' kick. "The shot didn't have much power," Alfaro said through the interpreter. Terrence Boyd scored twice for the U.S., and Johnson replaced keeper Bill Hamid in the 39th minute. After a 2-0 loss to Canada in the second of this three-game, round-robin tournament, the Americans needed to win to advance. So did El Salvador, and the crowd of 7,889 was about evenly split between the countries keeping the U.S. from a true home-field advantage at LP Field, home of the NFL's Tennessee Titans. El Salvador survived a physical game with plenty of yellow cards on each side. Boyd went to the sideline with blood on the front of his shirt late in the game. Diskerud said both he and Adu were bitten and showed reporters marks as proof. "Part of the game, I guess," Diskerud said. The U.S. had a little bit of time left to try and go ahead but couldn't get anything going before the game ended. The result leaves the Americans adding 2012 to 2004 and 1976 as years they failed to qualify for the Olympics, missing out on a 15th appearance overall. Boyd got his first start in this round-robin tournament with Juan Agudelo recovering from surgery in New York to fix torn cartilage in his left knee, and Boyd gave the Americans the scoring boost they missed against Canada on Saturday night. The Americans attacked from the start, Boyd scored 61 seconds into the game. Brek Shea dribbled out of three defenders and sent a cross over to Boyd who scored off a left-footed volley. And Boyd nearly scored twice more. His header went over the crossbar in the 10th minute, and he had a breakaway chance in the 11th only to see keeper Yimy Cuellar come out to break up the play. Hamid rolled covering up a ball and appeared to hurt his ankle midway through the first half. El Salvador took advantage by scoring two goals in two minutes to grab the lead and the momentum. Blanco scored on a header off a corner kick over Hamid's hands in the 35th minute, and Flores beat Hamid in the 37th minute off what had been a weak shot by Alas that turned into a cross. U.S. coach Caleb Porter pulled Hamid in the 39th minute, putting in 6-foot-4 Johnson for his first appearance in this round-robin tournament. Boyd tied it up with his second goal off a pass from Adu in the 65th minute. Joe Corona, whose mother is a native of El Salvador, scored off a header just inside the left post off a pass from Adu. Johnson smothered one strong kick from Isidro Gutierrez but couldn't stop the ball when it mattered at the end.

Kaboom! Last-Min Tournament Fun Facts! (Things to know when filling out your bracket)

*Only 6 teams since 1979 have started the season No. 1 and entered the tournament ranked No.1 overall and have gone on to win the tournament.

*Since the NCAA started seeding teams in 1979, only once have all #1 seeds made it to the Final Four (2008)

*For the past 20 years; only 4 teams entering the tournament with only one loss have made it to the final four, and none have won a national championship. (Good thing no one has that this year)

*Since 2000 no Big East team has made consecutive trips to the Final Four. (Sorry UConn)

*The last time a team that was No.1 overall at the start of the tournament has gone on to win a national championship was North Carolina in 2005.

*The lowest seed to win a national championship since 2000 has been a No. 4 seed.

*No. 14 seeds have won two tournament games in the same tournament just twice since 1985. (1986 and 1995)

* A No. 5 seed has made it to the Final Four 5 times since 2000. (3 out of the 5 have been teams from the Big-Ten)

*Two No. 11 seeds have gone to the Final Four in the last six years while neither a No. 10 nor a No. 12 seed has ever made it past the Regional Finals. 

*They only time all 1,2, and 3 seeds made it to the Sweet 16 was in 2009.

*Since 2000, Michigan State has the most Final Four Appearances with five appearances. (They have 7 Sweet 16 appearances in that timeline as well.)

*A No. 1 Seed has made it to the Final Four 30 of the last 33 NCAA tournaments.

*Carmelo Anthony is the only Freshmen to ever lead a team to a National Championship in 2003.

*No team as a #16 seed has ever defeated a #1 seed.

*Only three times in tournament history has a none of the No. 1 seeds made it to the Final Four. (Last time was in 2011)

*3 of the past 6 NCAA Tournaments a mid-major has made it to the Final Four. (They currently have a two year streak going right now.)

*The last team to win a National Championship in the Pacific Time Zone was Arizona in 1997.

*Since 1989 the No. 3 Seed has made it to the Final Four 12 times (No. 3 Seeds have won 4 NCAA Titles in that time)

*Since 1983 only Duke Maryland, or North Carolina have been the only ACC teams to ever make it to the Final Four.

*Last time Duke and North Carolina were both in the Final Four was in 1991. (Duke won the title that year)

*Since 2009 the team that has won the Big East Tournament has made it to the Elite Eight. (Louisville won it this year)

*Since 2000, eight times has had two teams from the same conference make it to the Final Four in the same year.

*Two No. 11 Seeds made it to the Sweet 16 last year.

*8 of the past 12 years, the national champion have come out of the Midwest or East region.

Kaboom! 2012 Final Floor Picks: Duke, UNC, Florida State, and Missouri

 Kaboom! 2012 National Champion Pick: UNC!