Porsche set the two quickest times during a dry three-hour Sunday morning session at the FIA World Endurance Championship Prologue in Italy.
Neel Jani submitted a 1:32.020s best to put the 919 Hybrid shared with Andre Lotterer and Nick Tandy on top of the timesheets at the Autodromo Nazionale Monza.
The morning run presented the busiest session of the Prologue for both Porsche and Toyota, with each LMP1 manufacturer submitting 80-plus laps to make up for the rain-soaked segment the previous night.
Jani's time was backed up by Brendon Hartley in the sister 919, who came to within 0.004 seconds of the Swiss driver.
The two Toyota TS050s finished third and fourth, around a half a second off the pace.
WEC Prologue Sunday morning times
The only non-hybrid LMP1 car running at the Prologue ended its test early with engine issues.
ByKolles Racing arrived in Italy with a new Nissan engine package derived from the former NISMO LMP1 project, plus a raft of aerodynamic changes, but 'unspecified problems' meant the car only ran six laps on Saturday evening.
In LMP2, Mathieux Vaxiviere led the times for TDS Racing, with the Frenchman pedalling his team's ORECA 07-Gibson to a 1:36.078s marker.
GTE-Pro was once again topped by Kevin Estre in the #91 Porsche 911 RSR, whilst the Spirit of Racing Ferrari 488 paced GTE-Am.
The final three-hour session of the 2017 WEC Prologue takes place later today at 14:00 local time.