Scarlets consolidated their third position in the PRO12 with a 25-16 victory over Ospreys at Liberty Stadium on Saturday.
Three late penalties from replacement fly-half Aled Thomas helped head coach Wayne Pivac's side walk away with a much needed away victory.
The hosts took an early 10-3 lead through Josh Matavesi's converted try and Sam Davies' penalty before the away team hit back via DTH van der Merwe's touchdown, who added to an earlier Dan Jones three-pointer.
Davies and Jones traded penalties late in the first half as the sides went into the interval on equal terms.
Replacement pivot Thomas made a second half appearance and converted four penalties from the tee giving the title challengers a valuable win.
The Llanelli outfit are enjoying success in the PRO12, while their Liberty Stadium opponents face the realistic prospect of missing out on a European Champions Cup spot, next season.
Although Jones opened the scoring for the visitors, Steve Tandy's side appeared the most likely team to make something happen and they duly managed to find the breakthrough after 15 minutes.
Dan Evans found a hole in the opposition rearguard, shrugged off a couple of attempted tackles and passed to Matavesi, who strolled across the whitewash unopposed with Davies adding the extras.
Another three-pointer from the 22-year-old Ospreys fly-half moved the score to 10-3.
Good hands from the Scarlets forwards allowed Morgan Allen to get to within inches of the line and his off-load sent van der Merwe over.
After the Jones conversion, the respective kickers traded efforts off the tee as the teams went into the break level at 13-all.
The contest remained evenly poised in the second stanza, but the visitors controlled the initial stages of the half with Michael Collins surging through the defensive line.
That attack eventually broke down but they were rewarded for their endeavour with a Thomas penalty.
The replacement pivot then added another three points before a Davies penalty reduced the lead.
The Scarlets remained in command of the encounter and Thomas secured the victory with two late penalties.
Pens: Davies 3
Try: Van der Merwe
Pens: Jones 2, Thomas 4
Ospreys: 15 Dan Evans, 14 Jeff Hassler, 13 Ben John, 12 Josh Matavesi, 11 Eli Walker, 10 Sam Davies, 9 Rhys Webb, 8 Dan Baker, 7 Sam Underhill, 6 Dan Lydiate, 5 Rory Thornton, 4 James King, 3 Aaron Jarvis, 2 Scott Baldwin, 1 Paul James (c)
Replacements: 16 Sam Parry, 17 Nicky Smith, 18 Dmitri Arhip, 19 Adam Beard, 20 Olly Cracknell, 21 Brendon Leonard, 22 Dan Biggar, 23 Owen Watkin
Scarlets: 15 Steff Evans, 14 Gareth Owen, 13 Regan King, 12 Hadleigh Parkes, 11 DTH van der Merwe, 10 Dan Jones, 9 Gareth Davies, 8 Morgan Allen, 7 James Davies, 6 John Barclay, 5 David Bulbring, 4 Jake Ball, 3 Peter Edwards, 2 Ken Owens (c), 1 Rob Evans
Replacements: 16 Kirby Myhill, 17 Dylan Evans, 18 Samson Lee, 19 Maselino Paulino, 20 Will Boyde, 21 Aled Davies, 22 Aled Thomas, 23 Harry Robinson
Referee: Ben Whitehouse (WRU)
Assistant Referees: Ian Davies, Wayne Davies (both WRU)
TMO: Jon Mason (WRU)