Leinster Rugby's indifferent start to the season continued as they slipped to a second loss of the campaign away at Connacht, going down 10-9.
The defending champions had led 9-3 at half-time thanks to three Ian Madigan penalties but Kieran Marmion's solo try ensured Connacht - who had lost their previous 11 all-Ireland clashes - preserved their 100 per cent start to the season.
At the Liberty Stadium, Ospreys ran in nine tries against Edinburgh Rugby to consolidate their one point lead at the top of the table.
Scrum-half Rhys Webb got Steve Tandy's side off to a flying start by scoring two tries in the first quarter of an hour with Dan Baker also crossing the whitewash before half-time.
Hamish Watson replied with a try for Edinburgh just before the interval but Ospreys were able to find another gear in the second half.
In the opening ten minutes of the half Dan Biggar - scorer of 16 points in total - finished off a fine break from winger Jeff Hassler before the Canadian capitalised on a loose Edinburgh pass to run in from 80 metres.
And despite having Justin Tipuric sin-binned, the home side continued to assert their dominance, running in further scores from Jonathan Spratt, Hanno Dickinson, Tom Grabham and Tyler Ardron to consign Edinburgh to a record defeat.
Last season's runners-up Glasgow Warriors also continued their winning start to the season despite having to play much of the second half against Newport Gwent Dragons with 14 men.
Tyrone Holmes was dismissed 40 seconds into the second half for stamping but tries from Alex Dunbar, Josh Strauss, Tommy Seymour and Tim Swinson secured a 33-13 win - Dragons' points coming from Richie Rees' try and the boot of Angus O'Brien.
Ulster Rugby made it two wins in a row with a commanding 26-9 victory over Cardiff Blues at BT Sport Cardiff Arms Park.
The Irish province led 12-9 at half-time after a kicking duel between Paddy Jackson and Rhys Patchell.
But tries from Dan Tuohy - his third in as many games - and Ian Humphreys after the break proved to be decisive.
Elsewhere Munster claimed a first home GUINNESS PRO12 win since March with a 31-5 triumph over Zebre, Simon Zebo scoring a first-half hat-trick.
And Scarlets tasted victory for the first time this season as they beat bottom club Benetton Treviso 43-0, Gareth Davies and Liam Williams both scoring two tries.
TRY OF THE WEEKEND
With Connacht trailing to defending champions Leinster midway through the second half, scrum-half Kieran Marmion produced a moment of magic to turn the game on its head.
Making his 56th consecutive appearance, the 22-year-old picked the ball off the base of a ruck and escaped the attentions of Ian Madigan before bamboozling Rob Kearney with a side-step to run in and score.
BREAK OF THE WEEKEND
Dan Biggar may have scored Ospreys' fourth try in their demolition of Edinburgh but much of the plaudits should go to Jeff Hassler for his role in the build-up.
There appeared little danger when the Canadian received the ball in midfield on the Edinburgh ten-metre line but he spotted a gap in the defence to streak clear.
He was brought down just short of the line but the ball was recycled quickly to Biggar who saw off the attentions of two tacklers to touch down.
PLAY OF THE WEEKEND
After losing both their games to Newport Gwent Dragons last season, Glasgow Warriors were eager to set matters straight and they got off to the best possible start after a brilliant set-piece move.
Quick line-out ball was spread to Dorian Jones in midfield only for him to be met by a wall of Dragons defenders.
But Niko Matawalu claimed quick ball to feed Alex Dunbar who picked the perfect line to scythe through a gap to cross the whitewash.
PLAYER OF THE WEEKEND
Simon Zebo only scored four tries in the whole of last season but his treble against Zebre means he has already matched that tally this term.
The British & Irish Lion finished off good work from Andrew Smith, Ronan O'Mahony and JJ Hanrahan to set Munster on their way to a first home win in four attempts.
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