As with his late equaliser in the first leg against SK Brann in the last round, Roberto Lopes was the Shamrock Rovers hero once again with another vital Europa League goal.
And this time it was a second half winner as Stephen Bradley's side came from behind to beat a talented Apollon Limassol on another thrilling night before 5,524 at Tallaght Stadium in their second qualifying round tie.
Lee Grace levelled an early goal from Apollon captain Fotis Papoulis in a tight first half.
But Rovers were the better side after the interval with Lopes netting what could be a crucial goal ahead of the return in Nicosia next Thursday.
Such was the visitors’ frustration they finished with 10 men.
With nine different nationalities in their side, the Cypriots started with intent, forcing a corner inside 30 seconds with Ioannis Pittas bringing a comfortable save from Alan Mannus with an overhead kick from Emilio Zelaya's delivery.
Apollon maintained their positive start and were ahead from a stunning strike on five minutes.
Sloppy defending, first by Joey O’Brien and compounded by Sean Kavanagh’s poor clearance, was clinically punished by the slick passing visitors.
Zelaya and Sasa Markovic worked the ball to Papoulis who scored with a cracking half volley off his right foot to the top corner of the net from some 25 yards.
Despite the early setback, Rovers settled and began to trouble Apollon from Jack Byrne’s set pieces.
Spanish defender Hector Yuste saw an early yellow card for pulling back Dan Carr after Byrne had put him in behind.
From the resulting free kick Rovers won their second corner. And from that they were level on 14 minutes.
Byrne’s execution was once again superb. Central defender Grace met the ball with a firm header that went in off a post with Carr getting a touch also.
Apollon responded with a sustained bout of pressure on the Hoops goal, Zelaya forcing a tip over save from Mannus with a thumping drive from distance on 19 minutes.
From the partially cleared corner, Yannis Gianniotas worked Mannus again into conceding another one.
A further let off soon arrived for Rovers when Apollon had a goal disallowed for offside.
While Apollon enjoyed good spells with the ball they looked decidedly unsure defensively as Rovers continued to worry them when they got forward.
Grace’s header in behind on 38 minutes found the run of Carr whose cross-shot was clawed away by Swiss keeper Joel Mall.
Mannus was busy back at the other end just before the break, batting away a stinging drive from a tight angle from Papoulis.
Both sides were off target with free kicks early in the second half as Rovers came out with more belief.
And they raised the roof on the new south stand by taking the lead on 58 minutes from a training ground routine.
Byrne again whipped in a sublime free kick from the right for the near post run of central defender Lopes whose header took a slight deflection to find the net at the back post.
The woodwork rescued the Cypriots nine minutes later, Grace attacking yet another Byrne free kick to bounce his header on to the top of the crossbar.
Substitute Aaron Greene might then have stretched Rovers’ lead 11 minutes from time.
Beating the offside trap onto a ball over the top, Greene rounded keeper Mall, but shot way off target from out near the touchline as the chance was wasted.
Apollon’s Argentine midfielder Esteban Sachetti will miss the second leg as he was shown a straight red card on 85 minutes for a lunging tackle on Byrne.
Such was Rovers' second half superiority, Apollon’s only chance on goal didn’t arrive until deep in stoppage time when Gianniotas’ free kick was tipped over by Mannus.
Shamrock Rovers: Alan Mannus; Joey O’Brien, Roberto Lopes, Lee Grace; Ethan Boyle, Aaron McEneff (Dylan Watts, 85), Greg Bolger, Ronan Finn (Gary O’Neill 77), Sean Kavanagh; Jack Byrne; Dan Carr (Aaron Greene 64).
Apollon Limassol: Joel Mall; Joao Pedro, Hector Yuste, Attila Szalai, Vincent Bessat; Sasa Markovic, Esteban Sachetti; Yannis Gianniotas, Fotis Papoulis (Diego Aguirre 72), Ioannis Pittas (Serge Selom Gakpe 62); Emilio Zelaya (Facunda Pereyra 81).
Referee: Stephan Klossner (Switzerland)