Galway's impressively fashioned a victory that could yet have ruinous consequences for the Déise's title aspirations.
With defending champions Kilkenny scoring a priceless victory away to Clare, Waterford must now take at least a point from the Banner when they visit Cusack Park next Sunday to ensure qualification for the concluding stage in the title race.
No ifs or buts about the Walsh Park outcome, with Galway the undisputed masters virtually from start to finish. They struck for vital goals at crucial stages of both halves with full forward Eugene Cloonan helping himself to a hat trick and the outstanding Damien Hayes in the right corner scoring the other two.
The lethal duo made it a nightmare afternoon for a Waterford full back line that creaked initially before ultimately collapsing. The defence collectively came out of this one with little credit, while Waterford's attack seldom looked like breaching a rock solid Galway defence despite the herculean efforts of Dan Shanahan and John Mullane.
The Tribesmen won the toss and wisely decided to play with the assistance of a near gale force wind that swept into the city goal. But it was Waterford who opened the scoring with a sweetly struck Mullane point in twenty seconds.
A brace of pointed frees by Cloonan and another from play by Hayes quickly followed and they set down the marker that ultimately signposted the way for Galway's decisive win.
They were denied a goal as early as the 8th minute when David Tierney's pildedriver was brilliantly deflected out for a "65' by Ian O'Regan, but one could almost sense that Galway goals were on the way as they continually bore down menacingly on what was becoming an increasingly overworked Déise defence.
Two minutes later the Waterford citadel had fallen, clinical Cloonan the marksman as he gleefully capitalised on the gift a defensive blunder by Eoin Murphy presented him with.
To their credit they battled bravely into the teeth of the elements, spurred on by classy points from play by Paul Flynn and Shanahan. But Coonan struck again for his, and Galway's, second goal in the 19th minute, this time being superbly set up by the flying Hayes.
Their unflattering ten point half time lead, 2-10 to 0-6, was still far from an unassailable one but within four minutes of the restart it had widened to thirteen and barring a miracle Waterford were staring down the barrel of their first league defeat.
The third Galway goal was a score rich in quality, finished superbly by Hayes in the 39th minute and leaving Waterford with a veritable mountain to climb.
The decision to take Rory Gantley out of the attack and play him as both a third midfielder and even an extra defender at times worked a treat for the winners who had their victory wrapped neatly up long before referee Willie Barrett's final whistle confirmed it.
Flynn twice tried unsuccessfully for goals from frees, and though it was third time lucky for him when he rattled the rigging from a 20 metre free on 66 minutes there was still a three goal daylight between the sides.
Galway's hurling remained superbly assured, best epitomised by the excellence of David Hayes at centre back, Tony Og Regan in the middle of the field, and Hayes, Cloonan, and David Forde up front.
There was still time for them to further expose that alarmingly porous home defence as Cloonan connected overhead on Gantley's "65' and the ball sped past O'Regan without a chance of him keeping it out. Demolition job satisfactorily completed.
: Galway E. Cloonan (3-7, 0-4 frees, 0-1 "65'); D. Hayes (2-1); D. Forde (0-3); R. Gantley, A. Kerins (0-1) each. Waterford; P. Flynn (1-7, 1-6 frees); J. Mullane (0-3; D. Shanahan (0-2); D. Bennett (0-2, 0-1 free, 0-1 "65').
: L. Donoghue; D. Joyce, D. Cloonan, O. Canning; D. Hardiman, D. Hayes, F. Moore; F. Healy, T.Og Regan; A. Kerins, D. Forde, D. Tierney; D. Hayes, E. Cloonan. R. Gantley; Subs; D. Collins for Moore; A. Cullinane for Tierney.
: I. O'Regan; D. Coffey, D. Prendergast, E. Murphy; B. Phelan, T. Browne, L. Lawlor; M. Walsh, D. Bennett; J. Kennedy, S. Ryan, D. Shanahan; P. O'Brien, J. Mullane, P. Flynn; Subs; J. Murray for Murphy; E. McGrath for O'Brien.
Willie Barrett, Tipperary.