Connacht skipper John Muldoon came off the bench to score the match-winner against Samoa on a famous night at the Sportsground.
But while Muldoon made a storming impact on his introduction in the second-half, it was Eoin Griffin who gave optimism to Eric Elwood's experimental side, which produced a stunning display to win 26-22.
Griffin, with just a couple of Magners League appearances to his name, produced a superb performance, and Elwood gave his fringe players a chance -- Aidan Wynne, Miah Nikora, Eoin McKeon and Darragh Fanning were all involved.
There was no shortage of entertainment in an open first-half and twice Samoa looked like they would pull away, but Connacht hauled them back on both occasions.
Samoa scrum-half Junior Poluleuligaga created the opening try for blindside Misioka Timoteo on 19 minutes.
But the boot of Nikora hauled Connacht back with three penalties. However, sloppy defending undid a lot of work as Samoan openside Falemiga Selesele broke from the base of a ruck to dart over six minutes before the break. Out-half Lolo Lui maintained his 100pc record with another conversion to push Samoa 17-9 in front.
Connacht's response was excellent. Brian Tuohy raced in to score and Nikora added the points to leave it 17-16 at the end of the opening half.
Connacht hit the front for the first time two minutes after the restart when Nikora added another penalty after Poluleuligaga was sin-binned for killing the ball. Samoa regained the lead after 55 minutes with a fine break finished by sub Brando Vaulu.
The introduction of Muldoon and scrum-half Conor O'Loughlin lifted Connacht and they regained the lead when Muldoon barged over, and Nikora hit the conversion to seal the win.
Connacht: T Nathan; S Monahan (D Fanning 57), E Griffin, A Wynne, B Tuohy; M Nikora, C Willis (C O'Loughlin 59); R Loughney (R Sweeney 73), A Flavin (D Murphy 65), B Fa'amausili (D Rogers 51); A Browne, B Upton; E McKeon (J Muldoon 51), M McComish, E Taylor (S Conneely 73).
Samoa: M Pesamino; F Otto, U Setu, J Helleur, S Sinoti (B Vaaulu 52); L Lui, J Poluleuligaga (U Mai 52); S Lemalu, P Paulo, L Mulipola; C Slade (N Leleimalefaga 64), D Leo; M Timoteo, R Muagututia, F Selesele.