Striker Miroslav Klose scored the second-half goal which gave Germany three points in Group A yesterday to leave them second in the table after Turkey won 3-0 in Kazakhstan.
Germany, who finished third at the 2010 FIFA World Cup™, were made to work hard and Bayern Munich's Klose showed ice-cool finishing for his 51st-minute goal after Thomas Mueller capitalised on a rare mistake in the Belgium defence.
"I expected the Belgians to be as good as they were," said Low. "The victory was important, the team has shown plenty of spirit. Now we are very pleased to face Azerbaijan next week at home."
But Low admitted his side were not as slick as they had been at the World Cup and struggled in the first-half against a determined home side. "In the first half, we needed something to get going," Low added. "The combinations were not so sure of themselves as at the World Cup. In the second half, things got better because we had the match well under control.
Belgium now face Turkey in Istanbul on Tuesday in the next round of qualifiers and coach Georges Leekens said he was impressed with his young battling side, which included talented 17-year-old striker Romelu Lukaku.
"We had high hopes before this match, but we lost three points although my team fought well," he said. "The players wanted it and they created chances, but Germany were effective. What we saw tonight is a good basis for the future. This is not fantastic, but it was a promising game for us."
With Michael Ballack working his way back to fitness after the ankle injury which kept him out of the World Cup, Bayern Munich's Lahm captained Germany as he did in South Africa. "It was important we came away with the three points," said Lahm. "We know we have 13 months of qualifiers, we have a long and hard road ahead of us."
Belgium's defence allowed Germany few chances to score and Manchester City defender Vincent Kompany said they can now travel to Istanbul with confidence. "It's disturbing to lose as we had played well," said Kompany. "We must use this to get a good performance in Turkey on Tuesday.
"They did not leave much space for the Germans, we were well organised. It's a shame. We stood up to the third best team in the world, but in the end we were beaten."