The Standard Life GB men's team sustained a 95-62 defeat to Greece on Sunday night in Crete in their latest build-up game ahead of next month's EuroBasket.
The Greeks, one of the favourites to secure the European title in Slovenia, were put under pressure by Joe Prunty's side in the opening quarter and despite a team-high 15 points from stand-in captain Kieron Achara, the experienced hosts pulled away with a 22-5 run in the third period.
Head coach, Prunty will now ponder improvements ahead of a trip to Lublin to face Poland and Sweden later this week. He commented on tonight's opponents: "They're a tough team, one of the top teams in the world. But we didn't t bring enough of the physical presence we need on both ends of the floor.
"Our inability to protect our basket and defend on the perimeter is a big staple for us and that's something we need to concentrate on. Teams are getting open looks as well as getting the ball in the paint and we have to improve that. But everyone knows that and it's about better communication."
He could take some heart from how his side matched the former European champions in the opening quarter, despite the absence of regular skipper Drew Sullivan.
Achara hit a three pointer which put GB 16-15 in front after seven minutes as the Greeks were posed problems. However seven unanswered points took the hosts clear and another 16-4 run pushed them towards a 46-29 lead at half-time.
Britain cut the gap with an 8-0 burst but Kostas Kaimakoglu - who had a game-best 16 points - sparked Greece into an emphatic spell in which they hit five three-pointers in eight minutes.
And although Glasgow Rocks' Gareth Murray and Grimsby-born centre Liam Potter both contributed on their first GB appearances, they were destined for a losing debut as the Greeks pulled as much as 93-58 clear with two minutes left.
"We have to learn quick," said Achara. "We're going to get thrown into tough situations and as professionals; we have to respond to that situation. We have guys who are learning but they'll need to do it quickly."
Devon van Oostrum added 12 points for GB with Eric Boateng contributing 10. Andrew Lawrence and Alex Marcotullio did not play due to injury.
Great Britain suffered heartbreak despite a phenomenal effort from Harriet Ottewill-Soulsby as they were denied a first win at the U20 European Championship Women Division B after losing 58-56 to Montenegro.