Swansea striker Liam Cullen scored his first two Wales goals before second half strikes from Brennan Johnson and Harry Wilson continued Craig Bellamy’s unbeaten start since taking charge of his country in July.
Andri Gudjohnsen had fired Iceland into an early lead but defeat ensured they fall into a relegation playoff.
Wales still needed an unlikely favour from Montenegro to top the group but got it thanks to Nikola Krstovic’s hat-trick in Niksic.
Montenegro had lost all five previous games in the group and Juventus’ Kenan Yildiz looked to have restored order for the Euro 2024 quarter-finalists when he called out Krstovic’s opener.
However, the Lecce forward struck twice more in the second half to leave Turkey needing to win a playoff in March to gain promotion from League B.
© Agence France-Presse
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