Second-half goals from Christian Ribeiro, Karl Hawley and Damien Mozika were enough to give the Iron their fifth league win of the season, four of which have come on their travels, while the O's consolation came from a Kevin Lisbie penalty.
"We've got to keep smiling, it was a below-par performance which was a little bit disappointing," said Slade.
"In previous games we've had six, seven or eight players in really good form but we were struggling to find one or two in form.
"The biggest disappointment is the way in which all three goals were conceded. The first one we should have gone with the runner, then our keeper could have done better with the second - although we were asleep from the free-kick - and then we allowed the cross to go in for the third goal.
"Some of my players were not concentrating as well as they have done in recent games.
"The defeat has left us all a bit flat really, we've come back down to earth with a bump after our recent excellent run."
- Sports & Recreation
- Christian Ribeiro
- Damien Mozika
- Kevin Lisbie
- Karl Hawley