Orica Greenedge finished the 15.5-mile route in a team time of 25 minutes, 56 seconds. Omega Pharma-Quickstep was second just 1 second back
Team Sky came in third, 3 seconds off the pace. Saxo Tinkoff was placed fourth, 9 seconds back of the leading team, with Lotto in fifth and Garmin given the sixth spot, although both Lotto and Garmin were timed at 17 seconds slower than Orica Greenedge.
Omega Pharma-Quickstep, which was the second team off, put up the time to catch early and it stood until Orica Greenedge, which started18th among the 22 competing teams, charged in for the time trial win.
Gerrans, who won Monday's stage, takes over the overall lead from Jan Bakelants, whose RadioShack Leopard team finished well back.
However, Gerrans' teammates Daryl Impey, who is listed second, and Michael Albasni, considered third, have the same overall times as Gerrans after four stages. Michal Kwaitkowski is in fourth, 1 second back and Sylvain Chavbanel comes in fifth, also 1 second behind Gerrans.
Stage 5 Wednesday covers 142 miles in a relatively flat route from Cagnes-sur-Mer to Marseille.