Juventus boss Massimiliano Allegri hailed Cristiano Ronaldo and referee Paolo Valeri following the Serie A leaders' 2-1 win over Sampdoria.

Ronaldo took his tally for the season to 14 league goals with a brace in what was a VAR-dominated contest at the Allianz Stadium.

The Portugal forward gave Juve the lead with an early strike, and after that was cancelled out by a 33rd-minute Fabio Quagliarella penalty, Ronaldo converted a spot-kick himself in the 65th minute. Both penalties were awarded for handballs after Valeri had consulted the pitchside monitor, with the second decision looking harsh.

Sampdoria then thought they had drawn level in stoppage time through a superb strike from substitute Riccardo Saponara, only for the effort to be ruled out for offside once Valeri had again checked the replay.

Ronaldo was back in the champions' starting line-up after coming off the bench and netting an equaliser in the 2-2 Boxing Day draw at Atalanta.

Allegri was quoted on Juve's official website after the Sampdoria game as describing the 33-year-old summer signing from Real Madrid as "the best player in the world."

And he added: "It was important to end the year on a high and it wasn't at all easy.

"We had our chances against a good side, but we lost our way after their penalty.

"In the second half we restored our lead after several opportunities and almost conceded another at the end but thankfully it was offside.

"It's right to use VAR when it's considered appropriate to do so. Valeri officiated well and he was helped by technology.

"We played well but we were winning 2-1 at the and all we had to do was keep the ball without forcing anything. Instead we get caught on the counter too many times after losing possession. We shouldn't be making mistakes like that."

While Juventus' haul of 53 is a new Serie A record for most points registered in the first half of a season, Allegri was focused on another number as he said: "Thirty-seven, give or take a few, is the number of points we need to secure the Scudetto."

Ronaldo himself said: "The first half of the season has gone really well.

"We've won nearly all our games and we're a solid side but there's still a long way to go. We must stay focused and keep working away if we want to achieve great things."

Regarding VAR, Ronaldo added: "I like it a lot because it reduces the number of mistakes. It's not easy for the match officials to analyse everything that goes on in a match. We just have to let them get on with their jobs."

Sampdoria boss Marco Giampaolo made his unhappiness with the second penalty decision clear.

He was quoted on Sampdoria's official website as saying: "The team would have deserved a draw today, morally for me it's 2-2. And this I will tell my boys.

"For me the penalty given to Juventus is a gift. You can only give it if you've never played football, if you're a bureaucrat. Otherwise you never give it in life."

Giampaolo, whose side started Saturday in fifth place, added with a smile: "A goal like that of Saponara, (it) is a crime to cancel it.

"Also because the touch of the player who gives the ball is not clear. But I will not dwell on this.

"I do not feel defeated today."