Glentoran will face Cliftonville in the Europa League play-off final at Solitude on Saturday (3pm) after a night of high drama that also saw Newry City AFC promoted to the Danske Bank Premiership.
Linfield were 2-0 ahead against Glentoran at Windsor Park but their Big Two rivals fought back to triumph 4-3 and make the final.
Cliftonville hit back after the disappointment of their Irish Cup Final loss to Coleraine by sweeping aside Ballymena United 4-0 in north Belfast.
The Belfast rivals will now battle it out to make the European stage and pocket a £200,000 cash windfall.
The Sky Blues were up against it when Kevin Braniff was sent off in the first half and their challenge faded as Jay Donnelly and Joe Gormley both netted a brace.
Newry secured four promotions in five seasons after winning 3-1 at Carrick Rangers, sealing a 6-3 success on aggregate.
There were wild celebrations from the visiting supporters at the Belfast Loughshore Hotel Arena after the club returned to the big stage.