Irish are proving the great entertainers having scored a remarkable 18 tries in just two games to ensure maximum points in the group.
And their latest success - 67-9 at Lusitanos - also made sure they capitalised on a slip by pool rivals Stade.
The Exiles matched the nine tries they bagged against I Cavalieri Prato with another nine at Lisbon's Estadio Nacional to light up the first European cup tie to be held in Portugal for eight years.
Hooker Jimmy Stevens took his tally to three tries so far with a double that was equalled by Marland Yarde as the experience of the English Premiership club showed with seven tries in the second half.
That win took them a point ahead of Stade, who required a late conversion by Jerome Porical to overcome a stunning display by Prato who ended the game with just 12 players.
The Italians were rocked by a red card to No8 Giacomo Bernini just 23 minutes into the tie at Stadio Enrico Cheroni.
Yet they looked set to record the biggest win of the club's history following Abou Souare's try.
However two late yellow cards left them defending with just 12 men and they could not prevent flanker Nicolas Garrault crossing three minutes from time.
Porical still had to convert to clinch a dramatic 17-16 win but Stade slipped to second in the group ahead of those games against Irish.