Lisnagarvey pulled off one of the biggest comebacks of the season to book their place in the Irish Senior Cup final against Dublin giants Monkstown.
The Blues were punished three times for uncharacteristic mistakes by Three Rock in the semi-final at Hillsborough, but clawed them back in the last 23 minutes and progressed after a penalty shoot-out.
Coach Errol Lutton sent on Matthew Nelson near the end and the Wallace High schoolboy responded by slamming in the equaliser with barely two minutes left.
And in the shoot-out, veteran goalkeeper John Tormey saved the fourth penalty stroke to send the Blues through to the March 20 decider.
Luke Madeley put away a penalty corner, Freddie Morris scored on the backhand, and after Timmy Cockram missed a penalty stroke for Garvey, Conor Empey added Three Rock's third with a back post finish.
Michael Watt then roofed a beauty, Neal Glassey lobbed in a second and Nelson levelled to force strokes.
In the IHL, Peter McKibben earned Annadale a 2-2 draw against Cookstown despite the heroics of keeper Ian Hughes but it still leaves them three points adrift.
Meanwhile Instonians and Kilkeel are into the provincial play-offs following their wins over North Down and Civil Service respectively.
RESULTS: Irish Senior Cup semi-finals: Lisnagarvey 3 (M Watt, N Glassey, M Nelson) Three Rock 3 (L Madeley, F Morris, C Empey) (Garvey win 5-4 on penalty strokes); Glenanne 2 (D Keogh, S Boucher) Monkstown 6 (G Cole 2, G Watkins, L Cole, K Smith, J Bruton)
EY Irish Hockey League: Annadale 2 (M Allister, P McKibben) Cookstown 2 (T Sloan, R Millar)
Premier League: Kilkeel 7 (J Aiken 2, M Stevenson 2, G Russell, D Rae, E Agnew) Civil Service 2 (G Saunders, S Armstrong); North Down 1 (R Linter) Instonians 2 (S Kelso, W Robinson); Mossley 2 (D Glenny 2) South Antrim 2 (W Phillips, C Henry); Raphoe 2 (B Wallace 2) Newry 2 (J Taylor 2)
Irish Hockey Trophy semi-finals: Bangor 1 (B Burgess) Kilkenny 5; Queen's 1 (R Blair) Bandon 4