Liverpool midfielder Lazar Markovic played for the U23s against Crewe Alexandra last week.
Crewe Alexandra boss David Artell used the free weekend to bring his League Two side to Melwood where they trained with Neil Critchley's side and played a behind-close-doors friendly.
“It was another really good day and there are lot of reasons why we do it," Artell said. “It gives us a chance to have a look at their younger players. The change of environment is good for our players and they get to test themselves up against quality players.
“They respect where they are, having the chance to train for the day at Liverpool and they respect the players they are up against.
“They are usually younger but they also had Markovic with them and he was a class above. It was a great experience for them again and the players can really see the benefit of it."