Kelly Bailie scored the decisive penalty kick to secure the Challenge Cup for Glentoran in her final match as a player.
The contest between Derry City and Strabane District Council's club and Cliftonville ended in a draw after extra time, forcing a shootout at Windsor Park.
Cliftonville began the season finale aggressively, with Kirsty McGuinness deflecting a shot past stopper Ellie Scott before it went narrowly wide.
Glentoran responded with a well-timed pass from Charlotte Havern to Kirsty McGuinness, whose left-footed strike just missed the target in the first half.
The Reds maintained pressure throughout, but Glentoran's defence remained resolute, limiting scoring opportunities for Louise McDaniel and Caitlin McGuinness.
In the 68th minute, Cliftonville created their best chance when Vicky Carleton was gifted a great opportunity by Caitlin McGuinness before she failed to direct it on target.
Jess Foy converted the opening penalty kick for Glentoran, while Caitlin McGuinness missed her spot kick during the sequence.
Faye Loughan and Anna Rose Robinson exchanged penalties before Bailie finished her career with a powerful effort to win the match.
Naomi McLaughlin had two quick opportunities in the second half but both shots sailed over the crossbar, while Danielle Maxwell could not convert after good build-up play.
Mia Moore noticed Maddy Harvey-Clifford was offside and fired just wide, leaving chances at a premium until the final moments of extra time.
Ellie Scott made a super save to deny Toni-Leigh Finnegan from taking a late winner in the dying seconds of additional time.