The first games in the Mayo Girls Under 19 Cup were played over the weekend.
With Castlebar Celtic receiving a bye, Killala were first to book their place in the semi-finals when they won their north Mayo derby clash with Ballina 4-3 on Saturday.
Manulla saw off the challenge of Swinford on Sunday to fill the third slot, with Castlebar Town and Westport United due to meet next Saturday at 5 p.m. to decide the last of the four semi-finalists.
It was all even at half-time in Ballina, 1-1, after Killala broke the deadlock courtesy of Ciara Kearney on 26 minutes. But their hosts swiftly responded through Zuzanna Patyk three minutes later.
Killala tagged on two goals in a four-minute spell soon after the restart, Amelia Langdon up first followed by Kearney again.
Once again the Ballina reaction was swift, with Zara Daly adding her name to the score sheet just two minutes later, and Patyk had it level at 3-3 with 20 minutes left to play.
The deciding goal came in the 83rd minute as Killala progressed courtesy of Orla Adams.
A single goal separated Manulla and Swinford at full-time in their joust, with Nicole Ryan putting the only ball in the net on 49 minutes to give visitors Manulla a 1-0 win.
The first of the semi-finals is scheduled to take place next Friday when Castlebar Celtic will host Manulla (time to be confirmed).