But Team USA almost caught the home team, Britain, for the bronze, and that would have been a sensational story. These Americans have been together as a unit for little more than three months after standing on the brink of non-qualification in 2011.
That would have been an ultimate disaster for U.S. rowing, which once ran off eight consecutive Olympic golds in this forever-a-marquee Olympic event.
The quick-learning pupils of coach Mike Teti, rowing just their fourth race as a unit, got their act together faster than anybody might have predicted.
Three-tenths of a second kept them off the medal stand. Britain glided over the line in 5 minutes, 51.18 seconds, Team USA in 5:51.48.
Teti joined the U.S. national team after piloting University of California crews to national titles.
The jockey-size coxswain's job?
"It's like you're riding this horse in the Kentucky Derby and have all these horses around you and you have to maneuver your horse and get to the finish line," Teti said.
Two key elements: "Making the correct calls and keeping a cool head."
The eight men he commanded have been muscling their oars for big chunks of their lives. Vlahos has never pulled an oar in his life.
"I played a lot of different sports as a kid: soccer, baseball - you know - like most kids," the coxswain said.
"I actually got into rowing through baseball. One of my Little League coaches was also a Masters division rower. He asked me to come try it one day, and I just fell in love with the sport. I always loved being on the water. The rest is history, I guess."
"My job, first and foremost, is to steer us down the racecourse," Vlahos continued. "Nobody else in the boat is looking around. That's my job. They're relying on me to tell them where they are, on the course, where the other boats are. I call the race plan as we get down the course as a single unit."
In real life, Vlahos works as director of development for the Oakland-based California Rowing Club.
Earning an Olympic medal would have been an ultimate achievement for this long-shot American crew.