Connacht winger Conor McPhillips touched down twice as Galwegians surprised Belfast Harlequins with a 29-8 defeat at Crowley Park.
'Wegians, who had conceded 149 points to 'Quins in their previous three league meetings, came firing out of the traps to go 24-0 up at the break.
Centre Nick Wakley made two tries - one for the lively McPhillips and another for prop Ross Davies - and saw his midfield partner Anthony Barrett steal a loose ball from 'Quins out-half Niall O'Connor for a third.
'Quins did bite back early in the second half when wide man Gavin McLoughlin scored and O'Connor notched a 47th-minute penalty, but McPhillips' second try followed in a victory which has 'Wegians in a five-way tie at the top of Division One.
It was the result of the day at Glenina as 'Wegians, who finished 14th last season and were fortunate to avoid relegation, grabbed a deserved win over Andy Ward's much-vaunted 'Quins side.
The fact that Galwegians' Welsh-born coach Paul Young fielded nine newcomers, made what occurred all the more significant. Adding in memories of Quins' 68-10 demolition of Young's men last January, it was an astonishing turnaround.
'Quins badly underestimated their opponents and it did not help that Ireland Under-19 international O'Connor had a particularly bad day at the office for the visitors.
The 'Wegians back row unit of captain Ambrose Conboy, Connacht's Brendan O'Connor and provincial Under-20 player Aaron McGettigan were simply superb.
Wakley stroked over an eighth-minute penalty and made the initial incision for McPhillips to cross the whitewash on 18 minutes.
Returning number 10 Paddy O'Toole, back from a stint with Blackrock, converted. Just seconds after the restart, the luckless O'Connor was intercepted in midfield and Barrett raced in with O'Toole again converting.
Ward's headache worsened when the men from the West went 24-0 up before the break - another Wakley-inspired move ended with Davies plunging in under the posts.
'Quins did up the tempo in the second half when McLoughlin spun in at the corner and O'Connor notched a penalty – his first success from three shots. However, 'Wegians were just too good on the day and McPhillips carved through, in the final quarter, for his second try and his side's bonus point score.
'Quins will look to bounce back at home to Terenure College in a fortnight's time.
Scorers:
Galwegians: Tries: Conor McPhillips 2, Anthony Barrett, Ross Davies; Cons: Paddy O'Toole 3; Pen: Wakley.
Belfast Harlequins: Try: Gavin McLoughlin; Pen: Niall O'Connor.
