Jose Calderon scored 19 points, and Spain held off a late charge by Great Britain to post a 79-78 victory.
Pau Gasol added 17 points, and his brother Marc Gasol had 12 points for the Spaniards, who have won each of their first three preliminary games in Group B. They are now tied with Russia atop the group standings, and the two will play each other on Saturday.
Luol Deng had 26 points to lead the Britons, who fell to 0-3 in the competition. Great Britain nearly recovered from a 12-point deficit heading into the fourth quarter, but fell just shy.
Joel Freeland contributed 25 points in defeat.
Spain held a 61-48 lead after three quarters, but a Deng basket with 3:19 to play in the game brought Great Britain to within three, 68-65. The deficit became two following a Freeland shot with 1:25 to go, though Calderon responded with a fast-break basket to widen the gap back to four.
After a Deng turnover, Calderon made two free throws with 39 seconds left for a six-point margin, and he made four more important free throws in the final moments to seal the victory. Deng's three-pointer with eight seconds left accounted for the one-point margin of defeat.