Great Britain's hopes of qualifying for the second phase of Eurobasket are all but over, despite a comfortable 85-73 victory over Portugal in Panevezys.
The win, GB's first at the tournament in Lithuania, came with 31 points from Luol Deng and 17 from Mike Lenzly.
Coach Chris Finch's team took command of the game against Group A's bottom seeds in the second and third quarters.
But to reach the second phase, GB need to beat Poland by 58 points on Monday after the Poles upset Turkey 84-83.
GB were at last able to call on the experience of centre Robert Archibald after he was ruled out of the first three games with a stomach complaint and his presence under the basket helped the team's effort.
Neither side started well in an all-but empty arena but Deng's combinations with Dan Clark gave GB an early 10-4 lead. Although they finished the first quarter tied 16-16, Deng hit 10 points in a 17-8 run at the start of the second quarter and two subsequent threes from Mike Lenzly had GB in charge 44-34 at the interval.
Lenzly splashed two more midway through the third quarter to post his highest international score while Portugal, who qualified for the tournament through this summer's additional qualifiers, looked jaded despite Saturday's rest day.
Portugal managed to get their own shooting game going in the fourth quarter, but a 16-4 run did little to worry GB, who replied with six points in a row from Nate Reinking and Deng, who had spent the majority of the second half looking to create chances for other players.
"It's taken a while to get a win but we're proud of the first one we've got and hopefully we'll get another one [on Monday]," said Lenzly, who is a veteran of GB's other Eurobasket tournament in 2009 when they failed to win a match.
"We haven't played as well as we can in the first three games here but the guys made a lot of little plays and we scrapped and got a win.
"I'm just thankful I finally got some of these to go in - I've been having a tough tournament," added Lenzly, who was GB's best three-pointer at the start of the summer. "The guys were looking for me and thankfully the ball fell."
Deng, who added 10 rebounds and four assists to his 31 points in an assured all-round performance, added: "We've had a really tough schedule and today we've done something that hasn't been done for GB basketball in a long time.
The game against Poland offers GB a chance to leave Panevezys on a two-game winning streak, but Deng warned against taking them too lightly.
"I've watched Poland since we got here - they play some good basketball and they've got some good players," he said.
"We know that if we don't come with our 'A' game [on Monday], they're capable of beating us. So we're going to prepare for it and try to get another win."