They ran out 3-20 to 2-12 victors and face Dungarvan in the last four at Fraher Field on Sunday night.
Manager Fergal Hartley, however, believes there is more in reserve.
“There’s a hell of a lot of areas for us to improve on. Overall as a performance, I wouldn’t be overly happy. There’s a lot of things we could do better.”
Pauric Mahony (10 points) and JJ Hutchinson (1-3) reacted quickest to the danger for the Gunners when Paul Coughlan saw red early in the second period.
The were level (1-6 apiece) at the break. The game started in cagey fashion but exploded into life during the second quarter. On 21 minutes, Brian O’Sullivan played a delightful cross-field pass to Stephen Power and he fired to the top corner.
Lismore rebounded from that blow three minutes later when Paudie Coleman set up Dan Shanahan for a goal
Ballygunner upped the tempo in the second period. Shane O’Sullivan charged through the centre on 32 minutes and laid off for substitute Hutchinson to double in the air and give Seanie Barry no chance (2-7 to 1-6).
But the celebrations were short lived when another substitute, Paul Coughlan, received his marching orders for an off-the-ball offence.
Shane O’Sullivan got a handle at midfield for Ballygunner and they strung together four points on the trot. Harley Barnes clinched the contest when he stroked to the far corner with eight minutes left, while Brian Bennett whipped in a Lismore consolation goal.
Earlier in the day, Martin O’Neill rattled off 12 points as a second-half flurry from Mount Sion overpowered Abbeyside (1-21 to 0-15).
The Waterford panellist suffered an injury-hit 2013 but Mount Sion boss Anthony Kirwan was thrilled to see the dead-ball specialist back in full flight.
“It’s been a tough year for him and he’s gradually coming back and getting better and better. Fair dues to him,” said the manager.
After conceding four goals to Dungarvan in their last group game, moving Austin Gleeson to No 6 shored up the defensive unit.
“Together as a group, in terms of the team and the management, we had to sit down and look at ourselves and see exactly what had to be done. In fairness to the lads, they reacted,” Kirwan said.
An early goal settled Sion. On two minutes, Martin O’Neill’s delivery broke favourably for Richie Roche to net. Mark Ferncombe earned a penalty on 10 minutes but his tame effort was stopped and Mount Sion raced upfield and Gavin Carroll’s score put them five points up.
Richie Foley rebooted Abbeyside from centre-back and he popped up with four first-half points. Eoin McGrath snuck Sion 1-7 to 0-9 ahead at half-time.
Kirwan’s side stepped on the gas after the break, scoring three quick points before Ian O’Regan made a point-blank save from sub Mark Fives. O’Neill took over at midfield and piled on nine second-half points.
Austin Gleeson and Owen Whelan also excelled.
Gary Hurney was dismissed in injury-time for a second bookable offence.
The Monastery men now tackle De La Salle on Saturday at the city venue.
* Waterford SHC semi-finals: Saturday: De La Salle v Mount Sion (5.30pm, Walsh Park); Sunday: Dungarvan v Ballygunner (7pm, Fraher Field).