The anguish and pressure of penalty kicks ended the United States U20 men's national team World Cup run, as Serbia bested the U20s in Auckland.

U.S. goalkeeper Zack Steffen kept his side alive in the sixth and eighth rounds of the shootout, twice saving penalties that would have knocked them out earlier. A third time of asking after John Requejo Jr. had his spot kick saved proved fruitless, as Nemanja Maksimovic blasted a PK that Steffen couldn't reach, ending the team's run in the Southern Hemisphere.

Penalties were needed after 120 minutes of scoreless soccer as a shorthanded U.S. side adopted a more conservative approach short three attackers, with Jordan Allen (suspension), Maki Tall and Bradford Jamieson (injury) unavailable to head coach Tab Ramos. It was a valiant effort that came up short, as Tommy Thompson and Rubio Rubin had the best chances of the game but failed to convert.

Here are three thoughts from the game.

1. Vital experience for U.S. youngsters to experience penalties

How often is a U.S. side involved in penalty kicks in a knockout tournament? The event occurs a bit more frequently than perhaps before for U.S. sides, with the Under 17s needing PKs to secure their World Cup qualification.

But it's far from common for players in a U.S. jersey to have to step up and face pressure like this in a knockout tournament. And while the team narrowly flunked thest test, for each respective individual, it adds steel to his game, as they can use this disappointment to further a club career or start knocking on the door of the U23s or full team.

That's the point of tournaments like this. Place promising individuals into the fire, see who emerges unscathed. This group, with or without penalty kicks, already showed its talent, and while the defeat stings, it could end up sparking something special in those who use it as both motivation and a learning experience.

2. Steffen's star continues to rise

If it wasn't clear from the Round of 16 match where goalkeeper Zack Steffen saved a spot kick in the game's final ten minutes against Columbia, two possibly match-turning saves from Steffen gave the U.S. new life not once, but twice in the penalty shootout.

And while his teammates didn't rise to the occasion after the second save, Steffen's star continued to rise both in this game and at this tournament. The former Maryland goalkeeper is undoubtedly the best U.S. prospect in goal under the age of 20, and there's every indication that he could become next in a long line of U.S. talent between the posts. Don't be surprised to see him involved with the Olympic team over the next year.

Naturally, he'll have to strut his stuff at club level and prove his potential there first. His new club, SC Freiburg, was recently relegated to the 2. Bundesliga, potentially creating an opportunity for the former FC Delco goalkeeper to earn some playing time with the first team.

3. Injuries left the U.S. short of offensive options

Only four U.S. field players were available for substitution in the defeat: Erik Palmer Brown, Shaq Moore, Conor Donovan and Joel Sonora. That left Ramos with very few ways to really alter the team's attacking approach, and summed up one of the reasons it finished 0-0 after 120 minutes.

While it's lame to make the excuse, the injuries to Tall and Jamieson left Sonora as the only attack-oriented option from the bench, handcuffing the coaching staff. Basically, it came down to the eleven guys in the starting lineup to find a way past a fairly solid Serbia side, and save for a couple of decent looks, nothing came to fruition. At this stage of the tournament, Ramos was probably cursing Reading for declining the involvement of talented forward Andrija Novakovich.

Disappointment should be felt of course (as it clearly is from the players after the defeat), as advancing into the semifinals would've setup a match with Mali after the African side knocked out the Germans on penalty kicks. But given the circumstances surrounding the run and the character on display, credit goes to this group for getting so close to the final four of a major tournament.