Sir Alex Ferguson's reigning Premier League champions entertain Sunderland on Saturday evening on the back of defeating Tottenham on Sunday.
It was a welcome boost for United, who had taken just two points from their opening three games.
United goalkeeper van der Sar said: "We did not expect to drop too many points but we did that.
"Now we have to get some momentum going and try to go on a run of six or seven games without defeat.
"I do not think we have played badly, is just that we are not scoring.
"We have had a couple of injuries and suspensions up front so we are a little bit light in that part of the pitch.
"But I presume after the international break everybody is back again and then we can really start the season."
The match against Sunderland marks the return of former club captain Roy Keane, who is now in charge of the newly-promoted side.
Van der Sar said: "I did not play that much with Roy because he was injured but he was influential at United for so many years.
"He played with a lot of players here and they will be happy to see him.
"But after that it will be back to the order of the day and just getting the three points that we need to keep on going. We are not making any more of it than it is."
United boss Ferguson knows Sunderland will make a game of it with Keane at the helm.
"I was surprised he took them to the league title, " he said. "I thought they might make the play-offs.
"Sunderland, though, is one of those clubs with a long history of disappointment.
"But the expectation never changes and I can understand that.
"Their fans are not Johnny-cum-latelys. Sons, fathers and grandfathers support them through the years.
"I am sure that has a lot to do with the town's strong shipyard roots."
Striker Louis Saha returns to the squad after recovering from a knee injury. He has not played since suffering the problem against AC Milan in the Champions League last April.
Wayne Rooney (broken foot) and Gary Neville (thigh) are again ruled out through injury.
Cristiano Ronaldo is suspended while Ole Gunnar Solskjaer announced his retirement this week.
Brazil international Anderson could be involved, however, following a hamstring strain.