Lawson, driving with MP Motorsport, laid down a 1:33.188s in the morning session which was bettered only by Leonardo Pulcini (Hitech Grand Prix).
The afternoon session was slightly slower due to heavy rain not long before it got underway, although most switched to slicks in the latter stages of the day.
Lawson had been fastest in the wet running before being relegated to seventh for the session in the 30-car field.
Tasmanian Alex Peroni (Campos Racing) and Christchurch's Marcus Armstrong (Prema Racing) were fifth and sixth respectively in the morning session, and seventh and eighth on combined times.
Testing resumes on Thursday (local time).