Middlesbrough's promotion hopes were dealt a painful blow as Conor Coady gave Charlton a surprise 1-0 win at the Riverside Stadium.
Boro were hoping to keep up the pressure on Championship leaders Coventry with victory but instead dropped precious points in their pursuit of a place in the Premier League.
Coady's second-half winner leaves Boro eight points behind the Sky Blues, and more importantly just one ahead of a charging Millwall in third place.
It is nine years since Boro were in the top flight and they now face a massive last nine games in a tussle for a priceless top-two finish.