The Serie A side need a boost for the second leg in Turin after losing in-form midfielder Mohamed Sissoko to a broken foot in Saturday's 1-0 derby win over Torino.
"Now we can think of Chelsea. It will be difficult, we will need to be at our best and have the support of the crowd," former Chelsea coach Ranieri told reporters.
"Against English sides, the help and support of the crowd can count."
Juve's 30,000 seater Stadio Olimpico may be a far cry from their former 60,000-capacity Stadio delle Alpi, but the atmosphere can still be electric as Real Madrid found when they lost 2-1 there in the group stage.
Winger Marco Marchionni is doubtful but defenders Nicola Legrottaglie and Zdenek Grygera have shaken off knocks and should be fit to play.
Ranieri left Alessandro Del Piero and David Trezeguet on the bench against Torino, suggesting the striking pair will start against last season's runners-up.
COLE'S ARREST
Chelsea have been rejuvenated since Guus Hiddink took over from Luiz Felipe Scolari as temporary manager until the end of the season, winning all five matches under the Dutchman.
Even the diversion of Ashley Cole's arrest for being drunk and disorderly in the early hours of Thursday and the firm team meeting Hiddink held afterwards did not deter them from their quest for honours on Saturday.
Chelsea scored a routine 2-0 FA Cup quarter-final win at Championship (second division) side Coventry City to move into the semi-finals for the third time in four seasons.
The prize they really covet, however, is the Champions League, especially as they have played one more game than Manchester United and trail them by seven points in the Premier League title race.
Didier Drogba, who scored the only goal against Juve in the first leg at Stamford Bridge, netted his third in four matches at Coventry -- compared to three in total this season before Hiddink's arrival.
With Michael Essien back as a substitute for the first time in seven months following a knee injury and Ricardo Carvalho also returning on Saturday, Chelsea have a more familiar feel.
However, Nicolas Anelka may miss the match because of a toe injury and Paulo Ferreira is out for the rest of the season.
Probable teams:
Juventus: 1-Gianluigi Buffon; 4-Olof Mellberg, 33-Nicola Legrottaglie, 3-Giorgio Chiellini, 28-Cristian Molinaro; 7-Hasan Salihamidzic, 18-Christian Poulsen, 30-Tiago, 11-Pavel Nedved; 10-Alessandro Del Piero, 17-David Trezeguet
Chelsea: 1-Petr Cech; 17-Jose Bosingwa, 33-Alex, 26-John Terry, 3-Ashley Cole; 12-John Obi Mikel, 8-Frank Lampard, 13-Michael Ballack, 5-Michael Essien; 21-Salomon Kalou, 11-Didier Drogba
Referee: Alberto Undiano Mallenco (Spain)
