Great Britain followed up a stirring performance against Lithuania in their first Eurobasket game with a disappointing 90-61 defeat to Turkey.
GB fell behind 35-12 in the second quarter and rarely looked likely to close the gap against an experienced and disciplined Turkey outfit.
Luol Deng led GB's scoring once again with 22 points and Kyle Johnson added 10 in his first game of the tournament.
GB take on European champions Spain on Friday in their third group game.
When Britain found their early shots missing, Turkey were having no such problems, hitting five three-pointers in the first quarter as GB took almost eight minutes to register a field goal.
When Turkey did miss, their size and aggressive offensive rebounding had them recover more than half their missed shots at GB's end for second chances.
22-10 down after a quarter, GB then had to suffer a 13-0 run inspired by Turkey's 19-year-old centre Enes Kanter that left them 23 points down.
Although Deng kept the scoreboard ticking over, hitting 10 points in the second quarter, Turkey's lead was 44-26 at half-time as GB centre Joel Freeland struggled to stay out of foul trouble, notching just six first-half minutes.
GB's hopes of a recovery fizzled out in the third quarter as Turkey restricted Deng to just three points, stretching the lead beyond 20 points once again.
Finch's decision to offer extended playing time to 18-year-old Devon van Oostrum added some flair offensively, notably when the youngster dunked ferociously on Turkey 's NBA player Ersan Ilyasova as an act of defiance.
Another new player, Kyle Johnson, also showed that GB have young players waiting to take their chances, but GB were hardly ever in a game dominated by a well-drilled team that had the tools - particularly height and a good team ethic - to get the job done.
GB coach Chris Finch gave credit to GB's opponents after the game. "Turkey were excellent," he said. "They took control of the game early with their threes and their offensive rebounding - which we'd been concerned about."
"But we weren't aggressive early in the game - we were tentative, which we haven't been lately. We need consistency - we have to play consistently within ourselves."
Centre Eric Boateng accepted that GB were flat at the start of the game but said the team were not overawed: "I think mentally we never accepted that we couldn't compete. Credit to Turkey - they fought hard and we have to learn from this and prepare for your next game."
With only three of the six teams in Group C sure to qualify for the second phase, Finch said better shooting would be required. "We lost the three-point shooting tonight by 27 points," he said. "It's too obvious to see that that's the difference in the game."