The Great Britain men's water polo team suffered a 21-7 defeat against tournament favourites Serbia.
Team GB fought toe-to-toe with the Beijing bronze medallists for the first one-and-a-half quarters, but their opponents were lethal in the second half.
The Duke of Cambridge - a water polo player himself - cheered on alongside a full-house of 5,000 partisan fans, but the young British side were outplayed by a world-class opposition.
Serbia took the lead three minutes into the first quarter but Adam Scholefield, 27, from Leeds, drew the home side level, to the jubilation of the crowd. The two sides then traded goals, with captain Craig Figes, 33, from Bristol, first finding the back of the net with a penalty and then firing home from open play.
With the scores level at 3-3 after the first quarter, and 23-year-old goalkeeper Matt Holland, from Sutton, making some great saves, Team GB were clearly fired-up. They flew out of the blocks for the second period, and 24-year-old Rob Parker, from Cheltenham, blasted from five metres to give the home side the lead.
Two goals from Serbia put them ahead, before Ciaran James, 21, from Bristol, levelled the contest at 5-5. The Balkan team then started turning the screw, scoring five unanswered goals in the period to take it to 10-5 at half-time.
Another James goal early in the third quarter gave the home crowd something to cheer about, but the Serbs responded with six more goals before the end of the period. Figes pegged a goal back for Team GB in the final period, but his side looked fatigued as they leaked another five goals before the final whistle, to lose the match 21-7.
Serbia's star man was driver Andrija Prlainovic, who scored five times. Filip Filipovic found the back of the net four times, while Vanja Udovicic and Stefan Mitrovic scored hat-tricks.