ORIENT lost to Millwall today and never looked like they believed it would be any other way.
The visitors stayed on level terms at the New Den until the 70 minute mark, but that was because the Lions were toothless in front of goal.
Millwall captain Paul Robinson provided the break-through at close range with a simple tap-in when the ball fell at his feet, after Ben Chorley was beaten to a high ball in the box.
Then Steve Morinson made certain of the win, if it was not so already, from the penalty spot on 79 minutes.
Adam Chambers floored Scott Barron with a challenge which belonged on the rugby pitch. Keeper Jamie Jones guessed wrong and Morinson smashed high into the opposite corner.
Chorley did pull one back for Orient, on 90 minutes when he headed in from Jason Demetriou's corner. But it was a consolation which failed to set up a thrilling finale and prevent a first defeat for Slade as Orient boss.
This was a poor display by relegation-threatened Orient. Maybe the plan is to keep the powder dry for the crunch Wycombe Wanderers clash, next weekend.
Millwall could have won by more, but it was a low quality encounter all round, as neither side played like the game was very important in their respective campaigns, at opposite ends of League One.
Only Jason Demetriou, who impressed when Slade put him on for John Spicer, tested David Forde in the Millwall goal before Chorley scored.
The 69th minute substitute unleashed a low drive which brought a diving save from the keeper at his near post on 76 minutes.
Earlier in the game, Neil Harris somehow poked his effort wide from eight yards out, on 28 minutes.
The forward was put through one-on-one with keeper Jamie Jones after Chambers under-hit a back-pass to him in a melee.
Earlier, Marc Laird stroked his effort into Jones' arms when he was totally un-marked, ten yards out.
On loan Eric Lichaj shone at right-back as he soaked up the pressure from Danny Schofield and chums and broke attacks up. Little got past him.
Now the fight for survival rumbles onto next week when Orient have a must-win game against Wycombe Wanderers, at Brisbane Road.
Jones (gk), Chorley, Mkandawire (capt), Chambers, McGleish (Pires 85), Thornton, Daniels, Jarvis (Patulea 80), Spicer (Demetriou 69), Smith, Lichaj.
Subs not used: Morris (gk), Purches, Ashworth, Baker.