The narrow loss, following last week's 19-17 reverse against the Rhein Fire, leaves the Edinburgh-based franchise as the only team still without a win in the World League of American Football. However, neither side impressed in what the Barcelona head coach, Jack Bicknell, accurately described as an ugly game.
The most costly error in a match full of them came with nine minutes remaining, when Matt Blundin, the Claymores quarterback, was intercepted by the Barcelona defensive back Sean Thomas, who returned the ball to Scotland's 28-yard line. Four plays later, Scott Szeredy converted what proved to be the game-winning 37-yard field goal.
The Claymores had taken the lead in the first quarter when Blundin, allocated to the World League by the Kansas City Chiefs, capped an impressive drive with a 19-yard scoring pass to his fellow Chief, Allen DeGaffenreid.
The Dragons restored parity shortly afterwards when the quarterback Casey Weldon, on loan from the Tampa Bay Buccaneers, found the receiver Mario Henry with a 43-yard completion.
At that stage, a high-scoring game looked likely; instead, defences took over as the quarterbacks got the jitters.