- Former captain Edin Dzeko returned after being sidelined following a falling out with Fonseca, but the Bosnian's presence did not lift his side.
ROME: Evergreen striker Cristiano Ronaldo scored the day after turning 36 as Juventus overtook Roma to go third in Serie A on Saturday with a 2-0 win over the capital side as Napoli slumped in Genoa.
Juventus move five points behind leaders Inter Milan, who beat Fiorentina 2-0 on Friday, with a game in hand.
Second-placed AC Milan are one point off top spot before hosting struggling Crotone on Sunday.
Napoli missed the chance to pull level on points with Roma, falling to their second defeat in three league games, 2-1 against resurgent Genoa.
Ronaldo put Juventus ahead on 13 minutes with his 16th league goal of the campaign to extend his lead as Serie A's top scorer this term ahead of Inter's Romelu Lukaku.
The Portuguese striker, who scored a double in the Italian Cup in midweek against Inter, ended his three-match league run without a goal.
The five-time Ballon d'Or winner missed other chances as he was denied by the crossbar in the 23rd minute and Roma goalkeeper Pau Lopez seven minutes before the break.
Juventus's second goal came 20 minutes from time when Roger Ibanez turned into his own net while trying to stop Ronaldo getting to a Dejan Kulusevski cross.
"We'd prepared for this sort of game," said coach Andrea Pirlo, whose side drew 2-2 with Roma the last time the teams met.
"In the reverse fixture, Roma employed the same tactic against us and this time we wanted to turn the game on its head tactically. "Morale is high. Defensively we're strong and we're more alert than we were before."
Pirlo has settled into his role as Juventus boss after a stuttering start to the campaign, with six wins in seven league games in 2021.
"You learn from matches and defeats. You learn something from every game, especially as it's so tactical in Italy and you can't play every game the same way," said the former Italian World Cup winner.
Ronaldo later tweeted: "Happy to score and help the team against a tough opponent! 3 important points!"
Meanwhile, Paulo Fonseca's Roma have still not beaten any of the other top eight teams this season.
Former captain Edin Dzeko returned after being sidelined following a falling out with Fonseca, but the Bosnian's presence did not lift his side.
Roma are two points behind Juventus in fourth, having played one game more than the Turin giants.
"We had more shots on goal (14 to 3), more corners (9 to 2), but it's the team that scores goals that wins," said Fonseca.
"A player like Ronaldo makes the difference. That's why he's the best in the world," he added of his fellow Portuguese.