Cristiano double against Lazio took Juventus a step closer to a ninth successive Serie A title on Monday.
Ronaldo opened the scoring from the penalty spot on 51 minutes from the penalty spot – his 50th Serie A goal – and doubled his tally three minutes later after Paulo Dybala teed him up in front of an open goal.
Ciro Immobile pulled one back for a Lazio in the 83rd minute, leaving him and Ronaldo tied on 30 goals in the race to finish as Serie A’s top scorers.
Victory took table-toppers Juventus to 80 points, eight clear of Inter Milan. with four games each to play.
Only one point behind Juve when the season restarted, Lazio have lost four of their last five games after being ravaged by injuries.
During an even first half, Alex Sandro headed against the post for Juve and Immobile thumped a low shot against the foot of the upright for Lazio in what was a rare sight of goal for the Italy striker.
The game swung Juve’s way after halftime when Ronaldo’s shot struck the arm of Lazio defender Bastos.
The referee awarded a free kick but, after a VAR review ruled that Bastos handled inside the area.
Ronaldo’s shot had just enough on it to squirm under Thomas Strakosha’s hand, making the Portuguese, 35, the first to score 50 or more goals in each of Serie A, La Liga and the Premier League.
“Records are always important, but the team victory is more important,” said Ronaldo.
“I’m helping the team to win. It’s important to win the title. There are four games left and we know that Serie A is a difficult championship.”
Three minutes later, Luiz Felipe lost the ball to Dybala who burst forward on the break and generously laid the ball off for Ronaldo to score into an empty net.
Ronaldo also headed against the bar but Lazio came back into the game when Immobile was tripped by Leonardo Bonucci after pouncing on a misunderstanding between the Juve defender and goalkeeper Wojciech Szczesny.
Immobile converted the penalty himself and Szczesny denied Lazio an equaliser when he palmed away a Sergej Milinkovic-Savic free kick.
Lazio pulled a goal back with seven minutes to go after a Bonucci foul on Immobile, who converted the resulting spot-kick.
“There is a bit of regret because after the lockdown we had a lot of problems,” said Lazio boss Simeone Inzaghi, whose side had beaten Juventus twice this season, in the reverse league fixture in Rome and the Italian Super Cup final.
“At the end of the game I congratulated the lads because despite the problems we showed character.”