Massimiliano Allegri's men have been held to a trio of draws in succession, playing out a goalless match with Atletico Madrid in the UEFA Champions League between league stalemates against Fiorentina and Sampdoria respectively.
As a result, Juve were forced to settle for a second-place finish in their Champions League group, while their lead over Roma at the top of Serie A has been cut to just one point.
Barzagli, who is nearing a return from an Achilles injury, is not worried about the champions' form, reminding critics that they are still top of the table.
"We played against three big, physical sides," the centre-back told Juve's official website.
"But the important thing is we're still top. It's a long season, and we have to stay as focused as ever."
Juve will be expected to take all three points away from Stadio Sant'Elia, with Cagliari having failed to register a single win in the last 10 meetings between the sides across all competitions.
Cagliari's last win over Juve came in the shape of a 2-0 triumph at home in November 2009, but few will envisage a similar outcome this time around.
Zdenek Zeman's side head into the clash third from bottom in Serie A, ahead of only Cesena and Parma.
Cagliari have won none of their last seven fixtures in the league, a run which includes home defeats to Fiorentina and Chievo.
He told Radio Rai: "The mentality of the lads was correct and we controlled the ball well, even if we were lacking something up front.
"It was hardly an epic match, as you could tell both teams were worried about their current situations."
