Adam Armstrong and Matheus Mane both missed several chances to put Wolves ahead after Cesar Peixoto’s side started the second half strongly.
But a composed performance from Bolton got them over the line, with Dalby hitting the target just six minutes after he came on as a 66th-minute substitute.
“It took really good discipline from our lads because it wasn’t easy,” Schumacher added.
“They committed loads of players on the top line and we needed the subs to continue giving us that energy to keep Wolves out because they’ve got top players and get people in really dangerous areas.
“Maybe they didn’t play to their best level, I haven’t seen every game they’ve played this year but our lads certainly did play to the top level and that was what it was going to require for us to get a result.”
Bolton are now 14th after 10 games and have won three out of their past four Championship matches but Schumacher said his side still have plenty to improve on.
He added: “We’re giving ourselves a good opportunity because we’ve got a good points tally but we can’t relax.
“As soon as you’re off it by a small margin, you get punished. The two back-to-back away [wins] are huge because that’s not easy to do.”