But there was no such luck for the Welsh as Edinburgh, Glasgow, Ulster picked up wins against the regions while Challenge Cup outfit Connacht also saw off the high-flying Ospreys.
Out of the four, only Newport-Gwent Dragons have registered a win in Europe so far this season but they were helpless to stop a last-gasp Brendan Laney penalty handing Pool 5 rivals Edinburgh a 16-17 win at Rodney Parade.
The game was deep into injury time when Laney stepped up to seal the points for the Scottish side and end the Dragons' unbeaten home record on the domestic front.
Chris Anderson's men now face a tricky trip to Connacht to get their title hopes back on track before welcoming Perpingnan to Newport for their Heineken Cup clash while Edinburgh travel to Rob Andrew's Newcastle.
With both sides set to meet at Hughenden in Round Three, it was Glasgow who drew first blood against the Scarlets with a 40-29 win on Friday.
The dress rehearsal for their crucial Pool 3 clash saw Kenny Logan inspire the Scots to victory with a brace of tries while the boot of Calvin Howarth ensured it was the hosts who were celebrating.
Having already beaten them at Ravenhill in Round One, Ulster proved their win over the Blues was no fluke with a 30-14 victory on Friday. Fly-half Adam Larkin was the key man for the hosts with his 15 points while tries from Andrew Maxwell, Campbell Feather and Matt McCullough ensured Blues' Lee Thomas' 14 points was mere consolation.
The Blues now face a daunting visit to Gloucester when the Heineken gets back on track while Ulster have an equally testing trip to Stade Francais.
Munster warmed up well for their Round Three clash with Castres with a convincing 45-8 win over the Borders while Pool 4 opponents Opsreys had their wings clipped by lowly Connacht.
The Musgrave Park crowd were treated to six tries from the Munstermen with Paul Burke grabbing 15 points to notch up their eighth Celtic League win on the bounce, perfect form ahead of their game in France.
But those at the Gnoll weren't quite as happy as they saw a depleted Ospreys team struggle at the hands of Connacht, Matt Mostyn grabbing the crucial score in the 10-9 win for the Western Irish outfit.
Lyn Jones' team head to London in Round Three for a must-win Heineken Cup meeting with NEC Harlequins.
CELTIC LEAGUE RESULTS
Fri 19th Nov Munster 45-8 Borders
Fri 19th Nov Dragons 16-17 Edinburgh Rugby
Fri 19th Nov Glasgow Rugby 40-29 Llanelli Scarlets
Fri 19th Nov Ulster 30-14 Cardiff Blues
Sun 21st Nov Ospreys 9-10 Connacht
WHAT'S COMING UP FOR THE CELTS
HEINEKEN CUP ROUND THREE
Leinster v Bourgoin
Glasgow Rugby v Llanelli Scarlets
Neath-Swansea Ospreys v NEC Harlequins
Castres Olympique v Munster
Newport-Gwent Dragons v Perpignan
Newcastle Falcons v Endinbrugh
Gloucester v Cardiff Blues
Stade Francais Paris v Ulster