The Northampton-bound outside-half played a starring role in three of Ireland’s four tries as they cruised to a 25-0 triumph over Emerging Italy in their first Tbilisi Cup clash.
The 22-year-old sent Eoin Griffin crashing over before showing his full range of ability to setup Andrew Conway and Stuart McCloskey in the first half.
They could not kick on in the second half, but Tiernan O’Halloran put the gloss on the victory with a well- finished try in the final play.
And 82-cap international Dempsey was impressed with what he saw from Hanrahan.
He said: “JJ controlled the game really well, we saw his full range of skills and he got to show his great passing ability.
“We saw his full skill set today, he passed well for the first try, he produced a pin-point kick for the second and made a great break for the third try.
“He really attacked the line which gave us good go forward (ball), but what really impressed me was his defensive effort.
“He had one of the highest tackle counts out on the pitch, which shows he’s desperate to impress.
“Everyone here is trying to impress with an eye on a World Cup squad place, but they stand more of a chance if they produce a collective effort and that’s what they tried to do.”
Hanrahan looked keen to impress from the off and he was the man to get Ireland on the scoreboard with a third-minute penalty after the Italy defence went offside.
The Northampton-bound outside-half showed off his playmaking ability 10 minutes later.
First he sent Stephen Archer barrelling down the middle before he got his hands on the quickly recycled ball to give centre Griffin a simple run to the try-line.
Italy prop Federico Zani was sent to the sin-bin for collapsing a maul five minutes later, and Ireland capitalised immediately.
Hanrahan was once again the architect as he delivered a perfectly weighted cross-field kick into the hands of Munster colleague Conway who crossed with ease.
The 22-year-old was at it again before half-time when he broke clear and ran 60 metres before unselfishly handing McCloskey the score, which he duly converted.
Ireland’s momentum stalled in the second period, but O’Halloran squeezed over in the final act to secure their winning start in Georgia.
Hanrahan was not the only on to impress Dempsey, despite Ireland’s underwhelming overall display.
He said: “It was a scrappy game, especially in the second half. There are guys here who are keen to impress and I think we tried to force the play and we pushed a few passes that didn’t need to be thrown.
“But I thought guys came off the bench and made a real impact, like Eoghan Masterson, Andrew Browne and John Cooney.”
T O’Halloran; A Conway, E Griffin, S McCloskey, M Healy; JJ Hanrahan, L McGrath; D Buckley (A Wawrick 74), R Herring (D Heffernan 54), S Archer (F Bealham 50), B Marshall, B Holland (A Browne 63), R Ruddock (c) (E Masterson 55), D Leavy, J Conan.
A Chiesa (c); F Guarducci (P Ceccarelli 30-37), R Quartaroli, G Massaro (G Benvenuti 28), G di Giulio; C Canna (S Negri 60), S Marinaro; F Zani (G Di Stefano 55), L Bigi (O Fabiani 48), G Iacob (P Ceccarelli 50), F Ruzza, F Gerosa (M Amenta 74), M Corazzi (C Canna 62), E Caffini (A Zdrilich 61), M Mbanda.
F Zani, Ceccarelli
Mathieu Raynal (France)