The Reds moved up to second in the Premiership thanks to a comfortable victory over the Glens at Solitude.
Chris Scannell toe-poked the ball into the bottom corner to give the hosts a deserved 23rd minute lead.
Glentoran improved after the break but Joe Gormley pounced on a Jimmy Callacher mistake before firing into the top corner to make it 2-0.
George McMullan added the third when keeper Elliott Morris got a hand to his shot, but the ball spun into the net.
Cliftonville are a point ahead of Portadown and four clear of Coleraine, who have a game in hand, as they chase the top-three finish to secure Europa League qualification.
Glens striker Andy Waterworth was lucky to escape a red card when he confronted defender Ciaran Caldwell in the closing minutes.
The visitors rarely threatened and Eddie Patterson's will finish the season bottom of Section A.