Albert Riera struck a stoppage-time winner as European champions Spain bounced back from a half-time deficit to defeat Turkey in Istanbul and further strengthen their stranglehold on Group Five.
Spain, who had beaten the same opponents 1-0 in Madrid on Saturday, had to do it the hard way after falling behind to Semih Senturk's 26th-minute tap-in but second-half goals from Liverpool duo Xabi Alonso and Riera earned Vicente del Bosque's side the spoils.
The victory means Spain, who have a 100% record after six matches in qualifying, are now a massive 10 points above Turkey - who many felt would be their biggest challenger in the pool - and six clear of second-placed Bosnia-Herzegovina, who were 2-1 winners over Belgium tonight.
Aside from that, the win also extended Spain's current unbeaten run to 31 matches - equalling the national record set under Javier Clemente in the 1990s.
Turkey enjoyed the better start at the Bernabeu on Saturday but this time it was Spain who threatened first through Riera's dipping 25-yard thunderbolt in the 13th minute.
It looked destined for the back of the net but Turkey goalkeeper Volkan Demirel produced a brilliant save to keep it out, sticking out his right hand and somehow managing to divert the ball over the crossbar.
Demirel was then called into action again seven minutes later, although this time he had a much easier job of saving Fernando Torres' low shot.
Six minutes after that, though, Spain found themselves a goal down.
Tuncay Sanli got in behind the visitors' defence to collect a dinked Arda Turan pass, and although the Turkey number 10 was unable to get a shot in himself, he poked the ball away from Iker Casillas and gave team-mate Senturk an open goal in which to slot home.
That was the only the second goal Spain had conceded since the group stages of Euro 2008 last summer, and on the previous occasion they managed to fight back from an early deficit against Belgium in October to record a 2-1 win.
A similar feat looked unlikely tonight though as hosts Turkey created two decent openings to increase their advantage either side of half-time.
Both were created by good work by Senturk and both were wasted by Nihat Kahveci, who opted to go for power over precision on each occasion and succeeded only in smashing his shots well off-target.
Turkey were made to play for the Villarreal hitman's profligacy as Spain drew level on the hour mark through Alonso's penalty.
Demirel made a hash of dealing with Xavi's corner and Torres, standing at the far post, sent a header goalward that was blocked at point-blank range by Ibrahim Uzulmez's arm.
The referee immediately pointed to the spot and Alonso coolly sent Demirel the wrong way to level the scores up.
With their tails up, Spain continued to press forward in search of second goal and Torres almost broke clean through only to lose the ball due to a heavy touch.
The Liverpool man had looked out of sorts up front on his own but he almost put the Spanish ahead in the 73rd minute when he latched onto a Santi Cazorla pass before sending a rising shot towards the top corner, only to see Demirel tip the ball over.
Turkey were not without an attacking threat of their own though, and Tuncay brought a good save out of Casillas diving away to his right with 10 minutes remaining.
Then came the knockout punch from the visitors as Riera slotted home his side's winner a minute into stoppage time.
Substitute Dani Guiza, who plies his trade for Fenerbahce in Turkey, collected a long punt forward and eased past his marker before feeding a low ball across the face of goal where Riera, in acres of space, had the fairly simple task of side-footing past Demirel.