Wayne Pivac's Scarlets are hanging in the Guinness PRO12 playoffs race and know they must win at Munster this weekend and hope Ulster falter at Ospreys to make the semifinals.
Scarlets, with Hadleigh Parkes and Michael Collins starting in the backline, defeated Dragons 34-20 in a Principality Stadium doubleheader before nearly 70,000 fans.
But their closest rivals on the table, Ireland province Ulster, also won, 30-6 over Leinster, to hold a one-point lead into the final round. Jared Payne scored a try for the Northern Irish team, while former Steelers loose forward Sean Reidy played at No 8. Isa Nacewa and Hayden Triggs both started for Leinster.
Pat Lam's Connacht hold second place but slipped up, 22-21 at Treviso, with Tom McCartney and Jake Heenan in the pack. Jayden Hayward kicked three goals for the home side, while lock Filo Paulo and first five Sam Christie also featured.
Glasgow Warriors, with Grayson Hart at halfback, seized the competition lead after punishing Zebre 70-10.
The Warriors travel to face Connacht in a top of the table clash which will determine home advantage through the playoffs.
Centre Francis Saili scored a try in Munster's 27-19 victory over Edinburgh, but the Irish are just out of the playoffs picture.
Brendon Leonard's Ospreys defeated Cardiff Blues 40-27 at the Principality, though Gareth Anscombe kicked six goals in a losing effort.
The semifinal picture is much clearer in England's Aviva Premiership, where Saracens, Exeter, Wasps and Leicester are all through.
Telusa Veainu scored another try in the Tigers' 31-17 win over Worcester, for whom Bryce Heem crossed for a five-pointer.
Teimana Harrison's try was decisive in Northampton Saints' 15-14 win over Bath. The Pisi brothers - Ken and George - both started for Saints.
A try to Johnny Leota was not quite enough, as Sale Sharks went down 12-11 at home to Gloucester. Bryn Evans and TJ Ioane both started for Sale, as did Willi Heinz, John Afoa and Jeremy Thrush for Gloucester.
Thomas Waldrom's Exeter beat Wasps and their Kiwi quintet 24-3, while Saracens headed Newcastle Falcons 23-14, with Richard Mayhew and Ruki Tipuna off the pine for the latter.
No less than nine New Zealanders appeared in the London Irish-Harlequins clash. The latter club won 32-25 with Ben Botica and Nick Evans sharing five goals, while Winston Stanley and Mat Luamanu also played. For the Exiles, wing Asaeli Tikoirotuma scored a try, and his teammates included Sean Maitland, Halani Aulika, Ben Franks and Chris Noakes.
The French Top 14 end line still feels a long way off, with still four rounds to play.
Castres, fighting hard with Bordeaux-Begles for a playoffs berth, did their cause no harm, David Smith scoring a try in a 37-6 win over Conrad Smith's Pau. Sitiveni Sivivatu was back on the other wing for Castres.
Ma'a Nonu's Toulon fell 12-10 at home to Toulouse, where Luke McAlister and Corey Flynn came off the bench. Racing-Metro, with Ben Tameifuna in the No 3 jersey, edged Clermont 26-20.
George Tilsley scored a try in Agen's 37-19 win over Brive, while Anthony Tuitavake's Montpellier hammered Steven Setephano's Grenoble 51-10.
Simon Hickey kicked four goals in a rare start at No 10 for Bordeaux-Begles as they beat defending champs Stade Francais 35-25. Luke Braid started at openside for the victors.
Oyonnax are still scrapping to avoid the drop, edging La Rochelle 17-16, with Roimata
Hansell-Pune, Leon Power and Viliami Ma'afu all featuring.