The Scarlets limped into the PRO12 play-offs after going down 41-17 to a rampant Treviso outfit on Friday.
The Welsh side knew they only had to win to confirm their place in the play-offs but were outplayed by their Italian visitors. Although, they did still make the semi-finals courtesy of the Ospreys' loss to Leinster at the RDS.
The hosts were the first to get on the scoreboard as young fly-half Owen Williams, who is on his way to Leicester Tigers next season, slotted over a penalty after a good early spell of possession.
Treviso responded well though, despite having little to play for, and their inspirational number eight Robert Barbieri scored his eighth try of the current campaign moments later.
He smashed his way over after the Italians had turned the ball over at a lineout and captain Antonio Pavanello had sprinted to within metres of the try-line. Kris Burton added the conversion and two penalties as the half wore on but nine more points from the boot of Williams ensured that the match was finely poised at 13-12 to the visitors at the break.
Treviso's prospects didn't look too healthy when they had both Valerio Bernabo and Jacobus Roux sent to the sin bin within a couple of minutes of each other soon after the restart but they survived admirably with only 13 men and even extended their lead.
After Burton was successful with two more penalty attempts, Fiji-born flanker Manoa Vosawai exploited an overlap and forced his way over in the left-hand corner to put his team ahead by two converted tries after Burton added the extra two points.
And the men from northern Italy romped away with the game in the final quarter, scoring two more tries to inflict an embarrassing defeat on the Scarlets.
First replacement Luca Morisi spotted some forwards in the defensive line and used his pace to get across the whitewash and then Burton put Christian Loamanu in the right-hand corner to seal a bonus point as well.
Liam Williams did score a late consolation try and while the Scarlets may still have made the play-offs as a result of the Ospreys' defeat to Leinster in Dublin, they will know that their performance will have to be much better to compete with Ulster in the semi-final.
Tries: L Williams
Pen: O Williams 4
Tries: Barbieri, Vosawai, Morisi, Loamanu
Con: Burton 3
Pen: Burton 5
Scarlets: 15 Liam Williams, 14 George North, 13 Jonathan Davies, 12 Scott Williams, 11 Andy Fenby, 10 Owen Williams, 9 Aled Davies, 8 Rob McCusker (capt), 7 Josh Turnbull, 6 Aaron Shingler, 5 Johan Synman, 4 George Earle, 3 Samson Lee, 2 Ken Owens, 1 Phil John.
Replacements: 16 Matthew Rees, 17 Rhodri Jones, 18 Jacobie Adriannse, 19 Jake Ball, 20 Sione Timani, 21 Gareth Davies, 22 Rhys Priestland, 23 Gareth Maule.
Treviso: 15 Brendan Williams, 14 Christian Loamanu, 13 Michele Campagnaro, 12 Doppies La Grange, 11 Ludovico Nitoglia, 10 Kristopher Burton, 9 Edoardo Gori,8 Robert Barbieri, 7 Alessandro Zanni, 6 Manoa Vosawai, 5 Antonio Pavanello (c), 4 Francesco Minto, 3 Bees Roux, 2 Giovanni Maistri, 1 Michele Rizzo.
Replacements: 16 Enrico Ceccato, 17 Alberto De Marchi, 18 Ignacio Fernandez-Rouyet, 19 Valerio BernabÃ², 20 Simone Favaro, 21 Fabio Semenzato, 22 James Ambrosini, 23 Luca Morisi.
Referee: Dudley Phillips (IRFU)
Assistant Referees: Neil Hennessy, Tim Hayes (both WRU)
TMO: Huw Lewis (WRU)