After two victories in the past week, Llanelli Scarlets and the Ospreys have eclipsed both Ulster and Connacht as the pace setters in the Magners League, and this week's Round 4 match-ups offer the Welsh regions the chance to go further ahead.
This Friday will see the Ospreys, who scored a comeback win over Border Reivers last weekend, travel to Belfast to face an Ulster team which will be smarting from their first defeat of 2006 (Ravenhill, kick-off 7.30pm). However if the Ospreys want to open a seven-point gap over the champions they will have to end a seven-match unbeaten home run for Mark McCall's men.
The Scarlets, who lead Ospreys by a point, will face Irish opposition again after their success in Connacht last Friday when Leinster travel to Stradey Park on Saturday (kick-off 5.30pm). Success for the region will allow them to equal an 11-match unbeaten record at home, and with Leinster having won on only one of their last 10 trips to Wales, the Scarlets will fancy ending the round still in pole position in the table.
Friday also sees Edinburgh Gunners travel to Connacht with the Scots having leapfrogged the westerners last week after their win over Ulster. The Gunners will be looking for an Irish triple in Galway (The Sportsground, kick-off 6.30pm) after also scoring a victory over Leinster in Round 2.
Elsewhere, Cardiff Blues and Glasgow Warriors also meet on Friday night, and with the Blues having slipped to two successive defeats, they will be eager to get back to winning ways against a Warriors team who scored their first win of the season against Munster last weekend.
However, the Warriors have been unable to string together consecutive league wins for nearly a year and have a poor record against the Welsh - scoring only one win in their last ten starts against the regions.
Border Reivers and Newport Gwent Dragons are Friday night's fourth pairing and the Scots will be looking to repeat their convincing win over the Dragons last May - which was their only win in the last 10 games. With Munster enjoying the free weekend, a win for the Reivers would also see them lifted off the foot of the table.