The Jaguar driver was already top of the times with a lap that would have been good enough to end the session fastest heading into the final five minutes.
But the Kiwi, who won both races in Rome last year, set a blistering final lap as he became the only driver to go below the 1m38s barrier, setting a 1m37.881s, which was 0.613 seconds faster than championship leader Jake Dennis.
