A Dan Jones penalty with the last kick of the match secured a nerve-wracking 20-17 win to maintain the Scarlets’ impressive early-season Guinness PRO14 challenge.
The scores were tied at 17-17 after Benetton skipper Tomasso Allan had struck a long-range kick two minutes from time.
But in a gripping finale, the Scarlets forced the Italians into an error from the kick-off then won the decision at the ensuing scrum.
It was left to Jones to show nerves of steel to slot the kick from 30 metres out to the right of the posts and make it five wins from the opening six matches for the West Walians.
The Scarlets dominated the second half, but were unable to break down a gritty Benetton defence.
In the end, it was another show of character from Brad Mooar’s side to claim the points in the dying moments.
Benetton, who arrived with 10 World Cup players in their squad, enjoyed the early possession but it was Scarlets who struck in bizarre fashion after just five minutes.
After an attack broke down in home territory, wing Corey Baldwin hacked through and showed a good turn of pace to kick on; the ball then pinballed between a clutch of Scarlets and Benetton bodies, a reckless pass was thrown behind his own line by Monty Ioane and while full-back Jayden Hayward waited for the ball to go dead, man of the match Steff Evans pounced.
It needed the TMO to decide whether the ball had grazed the whitewash, but television replays showed it remained in play.
Dan Jones converted, but Benetton’s response was strong with Italian fly-half Allan landing two penalty kicks to reduce the arrears to a point.
Josh Macleod was bundled into touch in the corner after a strong run by back-row colleague Blade Thomson, but the Scarlets had a penalty advantage and Jones made no mistake from the tee.
However, Benetton hit back immediately, pressurising the home line before freeing wing Angelo Esposito for an easy run-in.
Allan hit the upright with the conversion, but added a long-range penalty to push his side 14-10 ahead.
The Scarlets thought they had scored a second try by Lewis Rawlins just before half-time, only for the television match official to rule it out for a knock-on and Benetton were able to hold out for a four-point interval lead.
Looking for a strong start to the second half, the Scarlets came out of the dressing rooms with real purpose.
And they were rewarded with a second try after 54 minutes.
A series of drives took play up to the Benetton line and it was replacement prop Rob Evans, who had only just come on the field for loose-head Phil Price, who showed good strength to drive over.
Jones converted to give the Scarlets a three-point advantage, but the home side couldn’t pull away against a determined defence.
Werner Kruger came on to make his 100th Scarlets appearance with the bench making a big impact for the home side
Still though, Benetton were proving a tough nut to crack as time after time the home pack went close from their driving line-out, only for the visitors to hold firm and keep their line intact.
With just a couple of minutes to go the Scarlets were penalised for offside and Allan struck a superb penalty to level matters.
But the home side still had time to snatch the win and they managed to find a way thanks to the right boot of Jones.
After six rounds of the competition, the Scarlets are now second in the Conference B table, just three points behind leaders Munster.
Scarlets - tries: S. Evans, R. Evans. Cons: D. Jones (2). Pens: Jones (2).
Benetton - try: A. Esposito. Pens: T. Allan (4)
Scarlets: J. McNicholl; C. Baldwin, S. Hughes (capt), P. Asquith (repl K. Fonotia 58), S. Evans; D. Jones, K. Hardy (repl D. Blacker 67); P. Price (repl R. Evans 45), T. Davies (repl M. Jones 71), S. Lee (repl W. Kruger 55), L. Rawlins, S. Cummins (repl J. Kruger 63), E. Kennedy (repl U. Cassiem 55), J. Macleod, B. Thomson.
Referee: Andrew Brace (IRFU)