Luis de la Fuente's side were completely dominant and triumphed thanks to Mikel Merino's brace, as well as Atanas Chernev's own goal and a Mikel Oyarzabal penalty.

Spain have won all four of their opening matches, scoring 15 times without conceding a single goal to lead Group E ahead of Turkey and Georgia, with Bulgaria bottom after four defeats.

De la Fuente was without several injured key players including Lamine Yamal, Rodri Hernandez and Nico Williams, but his side made light work of the visitors in Valladolid.

Spain attacked relentlessly and came close to taking the lead when Barcelona midfielder Pedri Gonzalez's chip hit the bar.

Pedri was involved again when they broke the deadlock, with his lofted ball into the area nodded on by Robin Le Normand for Merino to head home.

Bulgaria coach Aleksandar Dimitrov admitted before the game his side were just trying to avoid a thrashing, and they restricted Spain to just one goal in the first half.

Borja Iglesias, who replaced Samu Aghehowa at half-time, should have extended Spain's lead but headed wide when well-placed.

Merino headed home his second of the game a few minutes later from Alejandro Grimaldo's cross as the hosts kept up the pressure. It was Merino's sixth goal in his last four matches for Spain.

Chernev bundled substitute Aleix Garcia's cross into his own net for Spain's third goal after 79 minutes.

Merino won a penalty in stoppage time as he was clumsily kicked by Martin Georgiev and Oyarzabal dispatched it to seal Spain's triumph.