Glentoran's challenge for the Irish Premiership title is hanging by a thread after they suffered a humbling 4-0 defeat by Crusaders at the Oval.
Declan Caddell and Philp Lowry scored in the first half, with Daniel Larmour and Paul Heatley finding the net after the break to complete the rout.
The Glens are six points behind leaders Linfield and five behind Cliftonville after those sides drew 0-0 at Solitude.
Glenavon came from a goal behind to beat Ballymena United 3-1.
That result sees the Lurgan Blues move four points clear of the Sky Blues in the battle to secure the seventh spot which would ensure participation in the end-of-season European play-offs.
Bottom side Warrenpoint Town kept alive their slim hopes of survival by beating Portadown 1-0 at Shamrock Park courtesy of Kealan Dillon's first-half penalty.
Carrick Rangers move up to ninth ahead of Dungannon Swifts on goal difference as a result of their 1-0 victory over Dean Shiels' side at Taylors Avenue.
Glentoran's lingering hopes of a first league championship success since 2009 were dealt a huge blow after their thumping by Stephen Baxter's side.
It was a match the Glens needed to win to stay in touch with the top two but they put in a dismal display against a Crues side who have now won their last five games in all competitions.
Caddell set the visitors on their way on nine minutes with a glancing header from Ross Clarke's cross finding the bottom corner.
Clarke's corner from the right was flicked on for Philip Lowry to poke home from close range and double the lead after 22 minutes.
A howler from keeper Aaron gifted Crusaders their third goal on 58 minutes as a weak Daniel Larmour header slipped through his grasp and into the net.
The impressive Clarke set up Paul Heatley to smash home a late fourth to seal a win which moved the fourth-placed Crues to within five points of the Glens.
VIA BBC