Dušan Tadić suffered late heartbreak at the World Cup, as Switzerland came from behind to take all three points in a crucial Group E clash between the countries.
Xherdan Shaqiri's 90th-minute goal, as he broke clear to coolly finish, completed an impressive second-half turnaround for the Swiss, who trailed 1-0 at the interval.
Saints midfielder Tadić had been an influential figure during the first half, in Kaliningrad, teeing up the opening goal of the match in the fifth minute.
His precise delivery from the right was perfect for Aleksandar Mitrović, who headed home to give Serbia the lead.
Tadić twice went close to scoring himself in the opening 45 minutes with two well-struck efforts from outside the area, the first of which was well saved by Yann Sommer in the Switzerland goal, before the second whistled just over.
Serbia’s lead was wiped out seven minutes after half-time, though, as Granit Xhaka’s glorious, curling strike from 20 yards fizzed into the far corner brought Switzerland level.
Sustained late pressure from the Swiss eventually then told, as Shaqiri broke through to slot a left-footed effort home and seal the three points.
The result means Serbia must take something from next Wednesday night's showdown with Brazil, in Moscow.
Serbia head into the game on three points, with both Brazil and Switzerland on four.