Moise Kean and Federico Bernardeschi were on target as Massimiliano Allegri's side closed the gap on the top four in Serie A to four points.
Kean put the host ahead in the 40th minute after it enjoyed 67.9 per cent of possession during the first half at the Allianz Stadium.
That figure slipped slightly to 59.3 per cent after the break as the Bianconeri allowed Cagliari a little more of the ball, though that seemed to provide Juve with more space in the final third as its shot count of 10 in the second period was double its first-half tally.
But before getting a second goal, Juve never looked truly comfortable. It dropped two points in similar fashion at Venezia 10 days earlier and was almost punished again as Cagliari saw two brilliant chances go begging – Dalbert narrowly failed to convert a cross, before Szczesny tipped over Joao Pedro's header.
Bernardeschi eventually secured a fifth win in six games with seven minutes remaining, but despite that and Juve's greater shot frequency, Szczesny was left frustrated by what he perceived as negativity and a lack of intensity from Juve.
"We worked hard, but I think there's a lot we need to improve still – both in defence and up front," he said. "Sometimes at 1-0, we relax and sit a bit too deep, but that's not good in the long run. We play arrogantly in those situations and I don't like it.
"It happened many times, including in Venezia when we conceded. We sit too deep in the second half. We can't keep lowering the level of intensity for 10 to 15 minutes every time.
"It went alright today, but we dropped two points against Venezia, so we can't keep doing that."