(writes through adding quotes)
* Serie A leaders Juve beat Sampdoria 4-2 in Turin
* Vidal double and Llorente, Pogba goals clinch win
* Roma eight points back after beating Livorno 3-0
By Terry Daley
ROME, Jan 18 (Reuters) - Arturo Vidal's double helped Juventus to their 12th straight league win with a 4-2 triumph over Sampdoria and saw the Italian champions restore an eight-point lead at the top of Serie A.
Antonio Conte's side moved on to 55 points from 20 games after taking the spoils from an entertaining encounter in which the visitors showed great heart and plenty of attacking intent.
"Samp are a team that came to our place and gave us a game. I think they can do good things over the rest of the season," said goalscorer Vidal.
AS Roma had briefly moved within five points of Juve after strolling past lowly Livorno 3-0 earlier on Saturday thanks to goals from Mattia Destro, Kevin Strootman and Adem Ljajic.
Third-placed Napoli, 13 points behind Juve, visit Bologna on Sunday looking to keep their slim title hopes alive (1400 GMT).
"It's a tough league. Roma and Napoli both have great players, but we need to carry on the way we've been doing up to now right to the end and hopefully we'll get our third title," added Chile midfielder Vidal.
He broke the deadlock in the 18th minute with a neat finish off the outside of his foot and, after Fernando Llorente headed the second from a corner six minutes later, Vidal took his tally to 10 this season with a penalty four minutes before halftime.
Three minutes before the spot kick was given for a soft-looking foul on Vidal by Vasco Regini, Sinisa Mihajlovic's spirited Samp side got back into the match when Andrea Barzagli diverted Manolo Gabbiadini's low cross into his own goal.
They reduced the deficit again in the 70th minute when Gabbiadini tapped home his fifth goal of the season on the rebound following a Gianluigi Buffon save from a corner.
The striker almost scored a shock equaliser three minutes later when he thumped a long-range shot against the bar.
However, Juve midfielder Paul Pogba then struck a powerful shot of from distance that flew into the top corner with 12 minutes left to seal the three points for the hosts.
"I don't think it would have been right for us to draw as Juve deserved to win. But we hit the bar and if that had gone in it might have gone differently," said Mihajlovic.
"But that's the difference, we hit the bar and they score a great goal through Pogba."
Rudi Garcia's Roma, with captain Francesco Totti starting on the bench, were on top from the start against Livorno with Destro scoring after six minutes with an easy tap-in, although their Ivorian striker Gervinho looked offside in the build-up.
A close-range Strootman strike nine minutes before the break and Ljajic's first goal since November with 12 minutes left saw Roma confirm their superiority in a devastating display which was blighted only by their profligacy in front of goal.
On Sunday, former Netherlands midfielder Clarence Seedorf returns to the san Siro to take charge of his old club AC Milan for the first time when they host Hellas Verona (1945 GMT).
Fourth-placed Fiorentina will aim to keep pace with Napoli, who they trail by five points, by winning at Catania (1400). (Reporting by Terry Daley; Editing by Josh Reich and Ken Ferris)