Scarlets came back from 14-0 down to post a bonus-point win against Treviso in the Pro12 League.
Full-back Ludovico Nitoglia and lock Valerio Bernabo scored the visitors' early tries at Parc y Scarlets, Willem de Waal converting both.
But Treviso were only a de Waal penalty ahead at the break after Josh Turnbull and Deacon Manu crossed.
Liam Williams and Liam Davies touched down after the break and Aled Thomas kicked 14 points.
Victory pushed Scarlets to fifth, above Cardiff Blues, in the table but their Welsh rivals have two games in hand on Nigel Davies' side.
The west Wales region also climbed over Ulster in the battle for play-off places.
Wales' squad players Aaron Shingler, Rhodri Jones and Lou Reed started on the replacements bench for hosts while the visitors were without 15 players because of injuries and Six Nations calls.
However, with Stephen Jones needed as bench cover in the wake of James Hook's withdrawal from the Twickenham clash because of illness, Aled Thomas was at 10.
The fly-half sent out some wayward passes, but his goal-kicking was spot on amid difficult conditions.
However, the game was barely underway when Nitoglia made his mark as he went over and Bernabo enjoyed his moment of glory after charging down fly-half Thomas' clearance to gather and score..
Hooker Emyr Phillips timed his pass to perfection for Turnbull to cut through Treviso's defence as Scarlets fought their way back into the game.
Scrum-half Gareth Davies' mazy run established the platform from which prop Manu was able to pick up and dive over, Thomas adding his second successive conversion.
However, de Waal ensured the visitors a slender half-time lead with the last kick of the opening period.
Shingler entered the fray eight minutes after the break as Scarlets continued to struggle to impose themselves on the contest with fellow new Wales cap Reed following him in the 63rd minute.
Reed took over from Dominic Day at lock, a day after the latter's end-of-season move to Bath was announced.
Fly-half Thomas missed a shot at goal, but was on target after another of the Scarlets' Wales squad members, full-back Liam Williams, cut a good angle to power over for their third try.
Thomas added a penalty before Treviso replacement Gonzalo Garcia and Shingler were sin-binned for separate illicit off-the-ball challenges.
De Waal and Thomas exchanged penalties before replacement scrum-half Liam Davies dummied his way through to earn the hosts' bonus-point try four minues from the end.
Scarlets: Liam Williams; Lee Williams, Gareth Maule (capt), Adam Warren, Andy Fenby; Aled Thomas, Gareth Davies; Phil John, Emyr Phillips, Deacon Manu, Dominic Day, Damian Welch, Josh Turnbull, Johnathan Edwards, Kieran Murphy.
Replacements: L Davies for A Davies (57), R Jones for John (52), P Edwards for Manu (70), Reed for Day (63), Shingler for Welch (48).
Not Used: Hawkins, O Williams, Iongi.
Replacements: Craig Hawkins, Rhodri Jones, Peter Edwards, Lou Reed, Aaron Shingler, Liam Davies, O Williams, V Iongi.
Treviso: Ludovico Nitoglia; Benjamin De Jager, Tommaso Iannone, Andrea Pratichetti, Brendan Williams; Willem De Waal, Simon Picone; Ignacio Fernandez Rouyet, Franco Sbaraglini (capt), Pedro Di Santo, Enrico Pavanello, Valerio Bernabò, Manoa Vosawai, Gonzalo Padrò, Marco Filippucci.
Replacements: E Galon for De Jager (73), A Di Bernardo for Williams (76), G Garcia for Picone (64), C Fazzari for Rouyet (64), E Ceccato for Sbaraglini (64), B Vermaak for Bernabo (64), D Vidal for Vosawai (72).
Not Used: A Allori.
Referee: Stefano Penne (FIR)
Assistant Referees: Tim Hayes and Chris Williams
Citing Commissioner: Richard Gwynn
TMO: Denis Jones