The title race will go down to the last day after both Linfield and Cliftonville failed to win their penultimate games of the season.
With Linfield being held to a scoreless stalemate against Larne, Cliftonville appeared to be in trouble when they fell 3-1 behind against North Belfast rivals Crusaders at Seaview.
Former Crues hero Colin Coates had given the visitors the lead, but Billy Joe Burns, Ben Kennedy and Jordan Forsythe put the hosts into a shock lead.
But two Ryan Curran goals pulled the Reds level and kept them in the title race for the final day.
Glentoran’s week went from bad to worse at the Coleraine Showgrounds.
Having had the news from the arbitrator that they will not be reinstated in the Irish Cup, they suffered defeat 24 hours later to Oran Kearney’s side.
A Matthew Shevlin penalty put the Bannsiders ahead but Michael O’Connor levelled the scores on 52 minutes.
Parity was only restored for seven minutes, however, as Aaron Jarvis and a second Shevlin strike restored Coleraine’s lead. Rory Donnelly pulled a goal back for the Glens on 90 minutes.
In the day’s other games Glenavon secured seventh spot and a place in the European play-offs with a win over Mid-Ulster rivals Portadown.
Danny Wallace’s 14th minute header was enough to give Glenavon the three points in a result which also consigns the Ports to the promotion/relegation playoff, where they will meet near neighbours Annagh United.
Goals from David Parkhouse, Mark Surgenor (own goal) and Leroy Millar gave Ballymena United a 3-0 win over Carrick Rangers.
And first half strikes by Marc Walsh and Ryan Mayse gave Dungannon Swifts a 2-0 victory over already-relegated Warrenpoint Town.