United are still without a win in the Premier League under the Dutchman after last Saturday’s 2-1 defeat at home to Swansea was followed by Sunday’s 1-1 draw with Sunderland at the Stadium of Light.
Juan Mata’s opener was cancelled out by Jack Rodwell’s equaliser but United struggled to create clear cut-chances against Gus Poyet’s side.
“Everyone has faith and believes in this club and our players because we have great players because it’s just a matter of time until the points come in,” Van Persie told Sky Sports.
“We lost two points [against Sunderland]. Clearly we came here to win. If you come in front after 15 minutes or so, we should have kept the score for longer. It’s always harsh to concede from a corner.
“In ball possession we were a bit too sloppy, lost too many balls, making it hard for ourselves.”