- Mateo Kovacic (20', 45'+4')
Wales, who beat Latvia 1-0, lead the group on four points on goal difference from Croatia with Turkey third with three.
Kovacic left Turkey goalkeeper Mert Gunok motionless when he scored from close range in the 20th minute following a failed attempt by the defence to clear the ball.
Kovacic scored again just before half-time as he tapped home a rebound after Gunok saved Mario Pasalic's effort.
Despite creating better chances early on, Turkey were kept out by Dominik Livakovic who made some exceptional saves.
In another blow for the hosts, Turkey captain Hakan Calhanoglu had to come off in the 36th minute due to an injury.
Turkey, who reached the Euro 2008 semifinals, are looking to qualify again after a disappointing performance at Euro 2020 when they lost all three games and scored one goal.
- Andreas Ekberg