Great Britain women suffered an agonising 64-63 defeat by Lithuania in their second group stage match at the Eurobasket finals in Bydgoszcz, Poland.
In their best display so far, GB had victory snatched from their grasp when Lithuania netted a pair of free throws in the final minute.
GB guard Natalie Stafford told BBC Sport: "There were lapses which lost us the game, it's heartbreaking."
Julie Page gave a strong display and led Britain's scoring with 19 points.
Stafford, 34, added: "It's disappointing right now but there's good things we can take from it. A year ago we might have thought this result was impossible.
"Lithuania won their group and we've only lost by one point so I think it will give us an extra boost and we'll come out fighting in the next game.
"I think that the loss will be good for us and make us more focused."
After winning the tip-off, Lithuania went on to score the first two baskets of the match.
But GB replied with zest to level the score before taking the lead with a three-pointer from Page to make it 5-4 after three minutes.
Despite their energy, GB allowed Lithuania's guards too much time to shoot from the arc and they punished GB. Lithuania went in at the end of the opening quarter 16-15 up.
The second quarter was tightly contested with little to separate the two teams. Azania Stewart came off the bench to lead Britain's rebound game.
With four minutes played in the third quarter, Britain had opened up a six-point lead at 40-34 as they continued to ask questions of the Lithuania defence.
Johannah Leedham continued her team's aggressive offence showing when, deep in the third period, the Chester-born player made a masterful feint to fool Lithuania's defence on the way to the basket and extend GB's lead to 49-46.
Britian held the lead for much of the final stages but were unable to gain a big enough lead.
However, even after Natalie Stafford's defensive foul allowed Lithuania to regain the lead at 64-63, GB still had the chance to cause a major upset in the final 20 seconds.
And with Page on the ball, GB looked ready to mount a final attack. But the 28-year-old lost possession and with it all hope of a GB victory.
The defeat leaves Britain needing wins from their final two games against Turkey on Saturday and Russia on Monday to make sure of further progess in their debut EuroBasket competition.
GB Basketball's performance director Chris Spice told BBC Sport: "We used an eight-player rotation and every player made a contribution.
"When you're just using that many players, you get a bit tired towards the end but you can't deny our effort, everyone gave 100%.
"We wanted to use this tournament as a springboard for the 2012 Olympics next year," Spice added.
"The way we've played so far shows we're not just here to make up the numbers we're serious about putting a marker down for the future."
Britain need to finish in the top four of a six-strong group to progress to the quarter-finals.