Charlton surrendered their 100 per cent start to the League One season after they were beaten 2-0 at Reading.
Charlie Savage broke the deadlock for the impressive hosts in the 66th minute, with a well-struck effort from distance.
Sam Smith made it 2-0 10 minutes later to effectively seal the home victory.
Charlton had won their opening three league games of the new season without conceding a goal.
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Reading were again watched by prospective new owner Rob Couhig.
The American financier, the former owner of Wycombe , has received EFL approval for his takeover but has yet to resolve the final details.
Royals dominated most of the first period, with Adrian Akande miskicking an attempted volley at goal and Ben Elliott driving a 20-yard effort wide.
Charlton gradually gained a foothold, with Tyreece Campbell firing off target before Luke Berry was superbly denied by Joel Pereira from close range following a precise Greg Docherty cross.
Though the visitors started the second period brightly, Royals went ahead when Savage drilled past Addicks keeper Will Mannion from 25 yards via a post.
It was Savage's third goal of the season and the first that Charlton had conceded in 336 minutes this term.
Smith soon doubled the lead when, after a quick break forward, he neatly tucked home Akande's excellent cross.