Glentoran suffered their second defeat in five days as two Jordan Owens goals earned Crusaders a morale-boosting win in the Premiership clash at Seaview.
Owens, who earned a Northern Ireland cap last year, put the Crues ahead on seven minutes and doubled the lead on 35 minutes after poor Glens defending.
The Glens improved in the second half with Sean Ward hitting the woodwork and Andy Waterworth going close.
But Gary McCutcheon and Timmy Adamson also missed further Crues chances.
Glentoran boss Eddie Patterson had been optimistic that his players could regroup from Monday's somewhat unlucky County Antrim Shield quarter-final defeat by Linfield.
That was Glentoran's first defeat of the season and it was more of the same in Saturday's Premiership contest as they paid for a slack first-half performance at Seaview.
Owen ran on to a long ball to hammer in the opening goal on seven minutes and as Crusaders continued to boss the contest, Paul Heatley then went close after an Adamson cross.
Poor Glens concentration led to the second Owens goal on 35 as McCutcheon crossed for the striker to score from close range after Gareth McKeown's long throw-in.
Glentoran's only effort of note in the first half was a Jim O'Hanlon shot which flew over just before the break.
The visitors did improve after the break as Waterworth tested Crues keeper Sean O'Neill and Ward then struck the butt of a post.
But the damage was done for the Glens by that stage as Crusaders earned a timely win after losing three of their previous four league games.