Van der Vaart almost turned provider as he sent in a delivery for Pierre-Michel Lasogga, who sent a header straight into the arms of the goalkeeper.
Lasogga should have given SV the lead just before half time when he caught hold of Jacques Zoua Daogari's headed pass, only for the keeper to save his effort at the bottom corner of goal.
Freiburg took the lead after the interval when Vladimir Darida tucked the ball into the bottom corner with his left foot.
However, the lead wasn't to last too long as Hamburger grabbed their equaliser through Lasogga, who lashed home with his right.
The SV man could have given his side all three points, but he was only able to skew a header wide following Van der Vaart's cross into the penalty area.