Great Britain's men were edged out 77-73 by Latvia in their first game of 2014.
Joe Prunty's side led with three minutes remaining, but an 11-3 run from the visitors turned the match in their favour.
Myles Hesson and Dan Clark top-scored for the hosts, with 15 points apiece.
"It was a great game," Prunty said. "We'd like to win but I thought we had a lot of positive things, in terms of moving the ball well."
Britain started well in their 100th senior international, opening up an eight-point lead in the first quarter at the University of Worcester Arena.
But Latvia, who finished two places above Great Britain at the 2013 Eurobasket tournament, reasserted themselves as the match went on, with point guard Janis Strelnieks guiding his side to victory in a scrappy final quarter.
Great Britain have an immediate chance to take revenge, as the two sides meet again on Sunday.
That meeting will be their final encounter on home soil before crucial Eurobasket qualifiers against Bosnia-Hercegovina and Iceland.