The Scarlets boosted their PRO12 play-off hopes by sealing a rare league double over Ulster with a 21-20 victory at the Kingspan Stadium on Sunday, and in doing so traded places with their hosts in the table.
Welsh region the Scarlets have been hit with a suspended fine after naming an ineligible player in their matchday squad for a European Champions Cup game.
Scarlets were grateful to a late penalty from replacement fly-half Aled Thomas as they snatched a 22-21 victory in a gripping Guinness Pro12 tussle at Parc y Scarlets.
Northampton boss Jim Mallinder praised a "good solid game" from England captain-in-waiting Dylan Hartley after Saints edged closer to the European Champions Cup quarter-finals.
A late penalty from Steven Shingler clinched a hard-fought 21-19 victory over Connacht at Parc y Scarlets to send the hosts back to the top of the Guinness Pro12.
The Ospreys claimed their 12th win in 15 games over the Scarlets, winning an entertaining Guinness PRO12 derby 27-26 in Llanelli – re-vitalising their play-off hopes.
Glasgow Warriors marked their 100th game in the European Cup by doing the double over Guinness PRO12 rivals Scarlets to stay in the hunt for a quarter-final place in the European Champions Cup.
Following a postponement in Paris and a home defeat to Northampton, Glasgow scored six tries to win their first European game of the season, beating Scarlets 43-6.
Glasgow head coach Gregor Townsend wants his men to learn lessons from their last meeting with Scarlets ahead of Saturday's European Champions Cup clash.