Cambiasso arrived at Leicester in August after 10 years at Inter Milan, and the Argentinian has been a vital player during the recent upturn in fortunes.
The Foxes recorded a third successive Premier League victory when they beat Swansea 2-0 on Saturday, and have hit form at a crucial time in their battle against relegation.
And former Leicester midfielder Birchenall believes the 34-year-old has now become accustomed to the tempo of the English game.
Birchenall said: “He’s been a revelation. When he first came he found it a little bit difficult, the pace of the Prem.
“But he’s adjusted to the pace now, he’s caught up, if anything he’s getting fitter, so now his influence in the last three games in particular has been fantastic.
“It’s just that, it’s around the place his demeanour, he’s just a quality guy, he’s got time for everybody and that’s what we like .
“He no big-time Charlie. I just love seeing him play and in difficult times just telling everyone to calm down. He’s been fantastic for us.”
Leicester are now third from bottom of the table one point behind Sunderland, who are two places above them with six matches remaining.
And the team travel to Turf Moor next Saturday to play bottom of the league Burnley.