Gonzalo Higuain scored two as Juventus marked boss Max Allegri’s 100th Serie A match in charge with a win that leaves them seven points clear at the top.
Higuain dinked a shot past Cagliari keeper Rafael from Claudio Marchisio’s pass before half-time.
He later slid Paulo Dybala’s pass under Rafael early in the second half to become this season’s joint top scorer in Serie A with 18 goals.
Cagliari midfielder Nicolo Barella was sent off for two bookable offences.
Barella, the home side’s best player, was already on a yellow card when he caught substitute Miralem Pjanic late from a Juventus throw-in.
Allegri’s side recorded a fifth successive Serie A win, restoring their seven-point lead after it had been cut by wins for Napoli on Friday and Roma earlier on Sunday.
Roma’s 2-0 win at Crotone moved then above Napoli into second – and came with a goal and a penalty miss from Edin Dzeko, who is level with Higuain on 18 league goals.
100 up for committed Allegri
Juventus’ manager has been linked with the job at Arsenal in recent days, amid speculation that Arsene Wenger may leave at the end of the season.
Allegri dismissed those suggestions before Sunday’s visit to his former club, stating he is happy in Turin and he hopes for “another 300 or 400 games” as Juve boss.
He has every reason to want to stay at present – his team have responded brilliantly to the tactical switches he has made since a surprising 2-1 league defeat at Fiorentina on 15 January.
That result prompted Allegri to abandon his 3-5-2 set-up in favour of a 4-2-3-1 formation so he could accommodate all of his key attacking players.
It has worked, as Juve have won five league games in a row since the change, without conceding a goal.
They were ruthless when their chances came; they waited 37 minutes for a breakthrough, scoring with their first serious effort on goal through Higuain, then broke from a Cagliari corner for a stylish second shortly after half-time.
Juve keeper Gianluigi Buffon was troubled just once, turning aside a 20-yard shot from Fabio Pisacane; at the other end, Rafael made a superb late save to stop Dybala’s close-range header after Mario Mandzukic had hit the bar.
Serie A round-up
England goalkeeper Joe Hart enjoyed a victory mixed with frustration, as Torino beat bottom club Pescara 5-3, having been five goals up before conceding three in a sloppy last 16 minutes.
Andrea Belotti scored twice for Torino to take his season’s total in Serie A to 17, but the home side lost their way, with Arlind Ajeti conceding an astonishing dragged backheel flick own goal as the visitors fought back.
Inter Milan overcame the absences of Mauro Icardi, Ivan Perisic and Marcelo Brozovic – and the disappointment of last weekend’s defeat by Juventus – to beat Empoli 2-0 and move into fifth, with Eder scoring the first and creating the second for Antonio Candreva. Atalanta rare fourth after winning 3-1 at Palermo.
Roberto Inglese got over the disappointment of seeing an early penalty saved by scoring his first Serie A hat-trick as Chievo won 3-1 at 10-man Sassuolo, while Sampdoria scored three in the last 10 minutes to earn a 3-1 victory over Bologna.