Former Arsenal midfielder Emmanuel Petit labelled defender Shkodran Mustafi 'king of the blunders' during punditry work in France.
The comments came as Petit assessed Arsenal's 1-1 draw with fierce rivals Tottenham at Wembley for RMC Sport, where Mustafi conceded the penalty from which Harry Kane converted.
'I was surprised to see him start,' Petit, a 1998 World Cup winner with France and Premier League winner with Arsenal, said. 'He is the king of blunders.'
Mustafi - a Germany international - played the full 90 minutes at right-back, with his push on Kane allowing Spurs to haul themselves level in the 74th minute.
Spurs had been trailing for much of the game at Wembley after Aaron Ramsey's 16th minute effort.
The draw leaves Arsenal fifth place, a point off of Manchester United in the battle for the top four.
Chelsea are a point further back in sixth but have a game in hand.
'I'm proud of the players, of our work,' Emery said after the final whistle . 'We played like a team. Our approach to the match was good and we could have won this match.
'We played with a big collective spirit, tactically we battled well. After 1-1, we tried to get the second and this is the mentality we want.'
Arsenal and Mustafi return to action on Thursday against Rennes in the Europa League.