The Irishmen had the dead eyed kicking accuracy of Paul Burke and a try by former Lion Rob Henderson to thank for the win which leaves them equal on points with the second placed Dragons.
However it's the Ospreys who are still setting the pace. The Neath-Swansea side recovered from their defeat by the Dragons last weekend to put Edinburgh to the sword on Friday night. Matt Jones was in fine form kicking 13 points for the Ospreys - while Stefan Terblanche and Andy Newman both crossed for tries in the 31-15 win.
Cardiff Blue's league renaissance continued with another home win - this time over Glasgow Rugby. Lee Thomas kicked 14 points to add to a first try for the Blues from Freddie Tuilagi and one from American Kort Schubert.
Although Calvin Howarth collected 14 points, and Andrew Wilson touched down it was not enough as the Blues held on for a 24-19 win which leaves them in sixth place - equal on points with Glasgow but with a game in hand.
Friday night saw The Borders and Ulster contest a basement battle - however it was the Borders who yet again come off second best against the current Celtic Cup holders. Ulster squeezed home 20-19 although they had led 20-6 mid-way through the second half and the win lifts them to eighth place while the Borders continue to languish seven points adrift at the foot of the table.
In the final game of the round Llanelli Scarlets ended a five-match losing run with a 24-22 victory over Leinster at Wrexham's Racecourse Ground on Sunday. Their nail biting 2 point win, courtesy of three tries to Leinster's one, saw them remain in 8th place, still the lowest of the four Welsh clubs, but they did close the gap on the teams above them.
NEXT CELTIC LEAGUE ACTION:
Friday 19 November
Newport Gwent Dragons v Edinburgh Rugby (Rodney Parade, 7.05pm live on BBC Wales)
Glasgow Rugby v Llanelli Scarlets (Hughenden, 7.30pm)
Munster v The Borders (Musgrave Park, 7.30pm)
Ulster v Cardiff Blues (Ravenhill, 7.30pm)
Sunday 21 November
Neath-Swansea Ospreys v Connacht (The Gnoll, 5.15pm live on Setanta/S4C)