(Adds Riga appointment)
LONDON, March 11 (Reuters) - Struggling Charlton Athletic have sacked manager Chris Powell and replaced him with Jose Riga following their FA Cup quarter-final defeat by Sheffield United at the weekend, the London club said on Tuesday.
"Chris Powell has been relieved of his position as first-team manager at Charlton Athletic with immediate effect," the Championship (second tier) club's website said.
Powell, 44, made more than 200 appearances for Charlton as a player and was appointed manager in 2011. His sacking means Norwich City's Chris Hughton is now the only black manager working in England's top four divisions.
Riga, 56, is a Belgian-born former Standard Liege boss who had been working in a technical capacity at AC Milan. He will take charge of his first game on Wednesday against Huddersfield Town.
Charlton are four points adrift of safety at the foot of the Championship table.
The club's Belgian owner Roland Duchatelet blamed a breakdown in contract talks for Powell's departure.
"We have been working with Chris Powell and his representatives for a couple of weeks to try and agree a contract extension which would have seen us continue to work together," he said.
"There was good progress, but we could not reach an agreement over the club's football strategy going forward.
"The situation put a strain on the working relationship between Chris and the board. Therefore I think it is best for all parties that we part ways at this stage." (Reporting by Martyn Herman; additional reporting by Toby Davis; editing by Justin Palmer)