Gareth Jenkins's side were coming off impressive League victories over Leinster, Cardiff Blues and the Dragons in their past three matches, but they conceded a try in only the fourth minute last night. Edinburgh lock Matt Mustchin bulldozed his way over and Chris Paterson added the extras.
Fullback Barry Davies, the forgotten man of Welsh rugby, reminded national coach Mike Ruddock of his talents with a clever chip-and-chase try as the Scarlets began to dominate, and displayed an extra string to his bow with an impressive penalty goal from the halfway line.
The Gunners hit back through hooker Andrew Kelly, who galloped 20 metres for a try, and the pack pushed scrum-half Mike Blair over the line for the home side's third try. The bonus point came through fullback Hugo Southwell, and Paterson's sideline conversion gave his side a 26-13 lead at halftime, with Scarlets winger Lee Byrne in the sin-bin for a spear tackle.
The Gunners lost backrower Simon Taylor and Kelly to the sin-bin as French referee Christophe Berdos confirmed his reputation as the card-loving official of the tournament, but the Gunners shrugged off the losses to score a fifth try through Argentinian winger Francisco Leonelli.
Byrne made amends for his 10-minute rest with a face-saving try in the final minutes, and five-pointers from backrower Alix Popham and replacement winger Tal Selley in injury time turned a one-sided match into a one-point win for the home side.
Edinburgh Gunners: Tries - M Mustchin, A Kelly, M Blair, H Southwell, F Leonelli; Cons - C Paterson 4.
Llanelli Scarlets: Tries - B Davies, L Byrne, A Popham, T Selley; Pens - B Davies, M Hercus; Cons - M Hercus 3.
Halftime: Edinburgh 26-13
Yellow cards: L Byrne (Llanelli Scarlets), Simon Taylor (Edinburgh Gunners), Andrew Kelly (Edinburgh Gunners), Hugo Southwell (Edinburgh Gunners).
Referee: Christophe Berdos (France)