The Reds second string hammered Sunderland 5-1 with the likes of Jay Spearing and Sebastian Coates at the forefront and Dalglish said it was a great hit-out ahead of next Tuesday's Carling Cup quarter-final at Chelsea which comes two days after the Premier League meeting with Manchester City.
"They applied themselves very well and they will be better for getting 90 minutes," he told the Liverpool Echo.
"They need to play games and it was good for them to be involved. It's better for them than training.
"Some people look at it as a form of punishment asking them to play for the reserves but that's certainly not the case.
"It was a necessity and it's important we give everyone opportunities to play matches.
"For the likes of Seb and Jay, it gives them the chance to get match fit and they did well. We need a strong squad with players who are ready to step in when they're needed."