Team GB suffered a 13-4 defeat to Romania in the opening game of their Olympic campaign at the Water Polo Arena.
The home side gave a spirited performance against tough opposition, but a poor conversion rate from man-up situations cost them vital goals. Sunday night's Group B game, in front of a partisan crowd of 5,000, was the first time since 1956 that Great Britain had entered a team in the Olympics.
The young team had targeted Romania in the so-called Group of Death, as their other opponents, Hungary, USA, Serbia and Montenegro filled the top four positions in the Beijing Games.
The eastern Europeans drew first blood through driver Alexandru Matei after centre back Joe O'Regan, 21, from Oldham, conceded a major foul. A string of great saves by goalkeeper Ed Scott kept Romania at bay, until Tiberiu Negrean managed to score past the 24-year-old from Leeds.
Captain Craig Figes clattered the woodwork during a power-play, but the 33-year-old from Bristol converted a penalty soon after to send the crowd into a frenzy and take the score to 2-1. The second period saw Team GB leak four goals while failing to score a single one themselves.
Romanian centre forward Cosmin Radu scored from close range, Nicolae Diaconu launched a long-range rocket past Scott before firing in another, and Ramiro Georgescu netted the fourth of the quarter. Great Britain did have chances to score. The period was punctuated by failed man-up opportunities, and a second Figes penalty found its way into the arms of Romanian goalkeeper Dragos Stoenescu.
Team GB will take positives from the third quarter, with centre-back Rob Parker netting twice from distance. The 24-year-old from Cheltenham scored once in open play and another in the only man-up opportunity in the quarter.
However, Romania also found the back of the net three times, with a lobbed goal from Dimitri Goanta, which went in off the crossbar, a breakaway goal from Diaconu to make his hat-trick, and a flicked goal from Negrean.
By the fourth quarter, Romania had opened up a lead of six goals, and the chances of an unlikely victory for the home side slipped even further away when their opponents widened the gap with goals from Andrei Iosep, another from Diaconu who scored from a free throw outside five metres, Alexandru Ghibhan and a second for captain Radu.
Jack Waller, 22, from Enfield, scored Great Britain's fourth and final goal of the match from a power-play. Team GB converted just two of their seven man-up situations, while Romania scored two from five.