Turning Point: Poland trailed 82-79 with 1:23 to go when Joel Freeland buried a three-ball
to give Great Britain a six-points lead with one minute to go.
Game Hero: Great Britain's Joel Freeland had 14 of his 27 points in the fourth quarter.
Stats Don't Lie: Poland were outrebounded 46-25.
Great Britain knocked Poland out of the EuroBasket after pulling away down the stretch for an 88-81 triumph in Group A.
The victory has catapulted Turkey into the next phase of the competition, with Orhun Ene's side not made to rue their shock upset by the Poles on Sunday.
All Poland needed was a win to join Spain and Lithuania in Round Two and they led 77-75 with 3:03 to go, but Britain outscored them 13-4 the rest of the way.
The result means Turkey, who were beaten by Poland 84-83, have clinched the third and final spot in Group A.
"We only have ourselves to blame," said Poland's Thomas Kelati.
"We made a lot of mistakes in the final quarter and that is down to a lack of experience.
"It depended on us and we blew it."
Great Britain's Joel Freeland had 14 of his 27 points in the fourth quarter and finished a perfect 12 of 12 from the floor.
He also pulled down 11 rebounds.
"We are just happy to win for ourselves," said Freeland.
"To go home with two wins is a good result for us."
Luol Deng contributed with a game-high 28 points and 14 boards.
Poland trailed 39-31 at the break but led 56-55 heading into the final frame.
The game remained close until Freeland, who will be one of his team's stars at next year's Olympic Games in London, stepped up for Team GB.
Poland trailed 82-79 with 1:23 to go when the Unicaja Malaga big man buried a three-ball to give Great Britain a lead of six with one minute to go.
The win is Britain's second straight after their triumph over Portugal on Sunday.
Dardan Berisha, Poland's hero against Turkey, had 19 points in defeat.
Great Britain out-rebounded Poland 46-25.