PSG were shocked by Reims, who beat them 1-0 despite going down to 10 men for the last 30 minutes.
Beckham denies that his side took Reims lightly and describes the game as "difficult".
"We had two good games against Marseille, but in football things change very quickly," Beckham told reporters after the match.
"We never think that we're superior to any team. It's always difficult coming to away grounds. I think they played very well but we can play better.
"They won the game so they must have done something better than us, but like I said, we move on."
PSG are now just two points above Lyon at the top of the Ligue 1 table.