Wolves had only a one-goal cushion until substitute Bakary Sako scored in injury time, for which Solbakken praised the Cobblers' organisation.
"The first half was tight and I had a feeling it would be, Northampton are a big side and very well organised," Solbakken said. "We knew it would be tough but as the game went along we got better and better.
"We should have killed the game off in the second half, we had four or five good chances inside the first ten minutes. But it was a good opportunity to give some players 90 or 60 minutes and some of the younger players did well."
Wolves have made a mixed start to their Championship season, winning, drawing and losing one each in their first three games.