Eyeing up a triumphant farewell ahead of the Euros, England’s night got off to the worst possible start when Jón Dagur Þorsteinsson fired Iceland ahead inside the opening quarter-hour.
Taking advantage of a rusty England backline, Þorsteinsson wrong footed Aaron Ramsdale, before drilling home the opener.
England’s response was fierce, albeit not successful.
Captain Harry Kane spurned the home side’s best chance of the half, with the Bayern Munich man skying high and wide after being picked out inside the box by Cole Palmer.
England stepped the intensity up after the restart and almost found a leveller, with Phil Foden creating space for himself in the final third, only to drag his effort wide of the target.
But it was at the opposite end of the Wembley pitch where the best goalmouth action came, with Iceland unlucky not to have found a second.
Goalscorer Þorsteinsson would’ve done just that if it wasn’t for an unfortunate slip, with the attacker seeing a close-range header smothered by Ramsdale moments later.
Keen to end on a high, Southgate turned to his bench, with Trent Alexander-Arnold and Eberechi Eze among those tasked with changing the game.
It proved futile though, with the Iceland backline seeing out the clean sheet with consummate ease.
Less than ideal preparation for England, who take on Serbia in Gelsenkirchen a week on Sunday.
Flashscore Man of the Match: Jón Dagur Þorsteinsson (Iceland)