Arnold said that his side should have scored more, but then were indebted to goalkeeper Diego Benaglio for keeping them level.
"Hamburg kept putting us under pressure towards the end, it became increasingly difficult for us," he told Bundesliga.com. "We have our goalkeeper and the woodwork to thank for snatching a point today.
"We also have to take our chances at the other end, that's why we lost control of the match today. It's a real pity."
The draw was Wolfsburg's sixth league game running without defeat.