The Spaniards spilled an 18-point lead in a 76-73 defeat by Lithuania, who also qualified for the knockout rounds to join the US and Argentina after they sealed their berths on Monday.
France, who are without their San Antonio playmaker and triple NBA champion Tony Parker, ground out a 68-63 success against Canada thanks to 24 points and seven rebounds from outstanding forward Nicolas Batum.
But the day's top performer was Batum's Turkish counterpart Ersan Ilyasova, who scored 26 points and buried all his six shots from three-point range in an emotional 76-65 win over perennial rivals Greece.
Wearing a mask to protect a facial injury, the Milwaukee Bucks forward carried his team throughout a rip-roaring contest in front of a raucous 10,000 home crowd in the Ankara Arena.
Greece power forward Antonis Fotsis was graceful in defeat and praised the home team, who got their revenge for a dramatic quarter-final loss to the Greeks in last year's European Championship in Poland.
"I think all the guys like to play in this kind of atmosphere, the fans created a great atmosphere and as a player you relish these occasions," he told Greek television.
"Turkey is a good team and they were certainly at their best today. All we can do is examine the game and look at what we need to do to correct the things we did wrong."
Centre Omer Asik added 12 points and six rebounds as the Turks applied transition from defence to attack with devastating effect, catching their rivals time and again with fast breaks and lethal long-range shooting.
Without Los Angeles Lakers centre Pau Gasol and injured Toronto Raptors playmaker Jose Manuel Calderon, Spain look a pale shadow of the side that won the 2006 event in Japan and the 2009 European Championship.
Having lost their opener to France followed by an effortless win against New Zealand, the defending champions need to win their remaining Group D matches against underdogs Canada and Lebanon to avoid an early exit.
They looked home and dry against the Lithuanians after taking a 61-43 lead midway through the third quarter but their offence then came to a screeching halt as the 2003 European Champions stormed back in Izmir.
Forward Linas Kleiza had 17 points and eight rebounds and three other Lithuanian players finished in double scoring digits to outmuscle the Spanish duo of Juan Carlos Navarro and Marc Gasol, who finished with 18 points each.
Russia stayed on course to reach the last 16 with an unimpressive 72-66 victory against Ivory Coast, centre Timofey Mozgov enjoying a game-high 19 points for the winners.
New Zealand and Puerto Rico kept alive their own hopes of progressing from their respective preliminary pools, the former easing past Lebanon 108-76 on the back of 26 points from Kirk Penney and the latter beating China 84-76.