Eddie Nketiah marked his return with a goal, while Matheus Franca stole the show with a second-half hat-trick.
Reflecting on the performance, Sage praised his players for executing the game plan after the break and said he was pleased with the team's response.
"We had problems with the ball and I think we have to work on this to be better,” he told club media.
"But at the moment the players are only able to play 15-20 minutes at the top level. It's only the first week, so we need more sessions.
"We've only had five sessions together. And we won't have just five anymore, so I think the next game will be better.
"But we have a good condition. We have a group who want to work with us, I think they give their best every day.
"I think this a good way to improve, both as players and as the team. I think we will continue like this."