Great Britain's men were beaten 77-73 by Latvia at the University of Worcester Arena on Saturday.
Britain were on the brink of victory as they led with just three minutes left on the clock but Latvia accumulated another 11 points to turn the game on its head.
Myles Hesson and Dan Clark were Britain's most potent players, scoring 15 points each.
The fixture was the 100th senior men's international since British Basketball's inception in 2006.
Britain face Latvia again on Sunday as they continue their preparation ahead of next month's EuroBasket qualifiers against Bosnia-Herzegovina and Iceland.