Pro12: Zebre 26-28 Scarlets
|Zebre (13) 26|
|Try: Biagi, Geldenhuys Con: Orquera, Garcia Pens: Orquera 3, Garcia|
|Scarlets (13) 28|
|Tries: S Williams 2, J Davies Cons Shingler, Priestland Pens: Shingler, Priestland|
Rhys Priestland rescued Scarlets with the final kick of the Pro12 game to boost their bid for an automatic place in Europe's top flight next season.
The Wales fly-half had already failed with one potential match-winner from the touchline before succeeding with the game's final chance.
Scott Williams went over for two tries with James Davies also crossing.
George Biagi and Quintin Geldenhuys tries helped Zebre push the visitors all the way.
Ulster also did Scarlets a favour by winning against Scarlets' mid-table rivals Connacht, who earned a losing bonus point.
And Wayne Pivac's side were also helped by Munster, who beat Edinburgh later on Saturday to help the west Wales region's cause after they climbed above the Scottish team into seventh.
If Scarlets stay there until the end of the season, their European Cup hopes will continue via a play-off with the English Premiership's seventh-placed team.
Whoever wins that game faces a mid-table French opponent with the final top-flight European slot at stake.
Pivac can only hope his forwards can improve after being tormented by a powerful home scrum and driving line-out.
Scarlets had mixed selection news ahead of kick-off.
Wales full-back Liam Williams made his first appearance since damaging a thigh in Wales' 61-20 win over Italy in the Six Nations on 21 March.
Centre and Wales team-mate Scott Williams also returned after recovering from a dead leg.
But dad-to-be Ken Owens was a late withdrawal so Ryan Elias came in at hooker with Torin Myhill on the bench.
Fijian wing Michael Tagicakibau was absent after he suffered concussion in Scarlets' 26-15 home defeat by Edinburgh on 28 March.
And Wales scrum-half Gareth Davies was serving a five-week ban for being sent off for a head-butt in that game.
Luciano Orquera kicked an early Zebre penalty and Steven Shingler replied.
Scarlets took the lead when flanker James Davies' good work set up Scott Williams' run to the line.
Shingler converted and added a second penalty before playing an unfortunate part in Zebre's opening try.
Fly-half Shingler failed to get under a high ball and lock George Biagi gathered to canter over, Orquera converting to level the scores.
Scott Williams' interception score put the visitors back into the lead early in the second period.
Priestland had taken over from Shingler a minute earlier and converted.
Orquera's final penalty before leaving the fray kept Zebre in the hunt.
And after lock Jake Ball was sin-binned on the hour, Zebre's pack took advantage with a second try from a lock, this time Geldenhuys charging clear.
Centre Gonzalo Garcia converted before Davies' try and Priestland's conversion put Scarlets back into a one-point lead.
With three minutes left Garcia kicked a penalty that gave the bottom-placed club's fans hope of a fourth win.
But after seeing one shot to win the game drift past the uprights, Priestland made no mistake moments later to seal Scarlets' win.
Zebre: Hendrik Daniller; Dion Berryman, Matteo Pratichetti, Gonzalo Garcia, Michele Visentin; Luciano Orquera, Brendon Leonard; Andrea De Marchi, Andrea Manici, Dario Chistolini, Quintin Geldenhuys, George Biagi, Filippo Cristiano, Mauro Bergamasco (capt), Andries Van Schalkwyk
Replacements: Oliviero Fabiani, Andrea Lovotti, Luca Redolfini, Samuela Vunisa, Valerio Bernabo, Guglielmo Palazzani, Alberto Chillon, Mirco Bergamasco
Scarlets: Liam Williams; Harry Robinson, Regan King, Scott Williams, Hadleigh Parkes; Steven Shingler, Aled Davies; Rob Evans, Ryan Elias, Peter Edwards, Jake Ball, Lewis Rawlins, Rob McCusker, James Davies, John Barclay.
Replacements: Torin Myhill, Phil John, Jacobie Adriaanse, Jack Payne, Rory Pitman, Rhodri Williams, Rhys Priestland, Steffan Evans
Referee: Gary Conway (IRFU)
Assistant referees: Elia Rizzo, Filippo Bertelli (Italy)
Citing commissioner: Achille Reali (Italy)
TMO: Carlo Damasco (Italy)