The former Barnsley striker netted twice inside seven second-half minutes to sink Crewe 2-1.
"That is what Chris is all about. He gets behind defenders and is very lively. He is going to be a great acquisition for the club," said Slade.
"It's great to go back on top and it was a really hard-earned result as Crewe were excellent. They put us under a lot of pressure, particularly late on in the game and we had to come from behind yet again.
"Our fans were fantastic all afternoon and in the last five minutes they counted massively for us as Crewe sent on a lot of big players and we had to pick them up on free-kicks and corners. We had to hang on."
Alex fans were daring to dream of a shock victory, but their hopes lasted for only eight minutes after Byron Moore's far-post finish handed Steve Davis' struggling side a deserved advantage.
Davis blamed defensive lapses of concentration for their second-half surrender.
"The game could have gone either way but swung Orient's because of a couple of errors at the back," he said.
"We couldn't build on our lead and one or two of the players seem to get nervous in those situations.
"Why? I don't know. Maybe it's the realisation of being one up against a decent side and having to hang on.
"And it comes down to the ability of the defenders to do their jobs. No-one is cutting us open or showing particularly fancy football. But it's always our mistakes and our switching off and they've all got to be accountable for that.
"Individual errors do cost you against the top teams.
"I thought Orient looked very ordinary and I thought we competed very well. But yes they have got good players which is why they are in the league.
"They were very clinical in their finishing and obviously Dagnall has done that before at this level."
- Sports & Recreation