The New Zealander turned a flying lap of 58.1516s around the 1.964-mile, 12-turn course to take the top spot with 18 minutes remaining in the 45-minute session. He led a Team Penske 1-2, besting team-mate Josef Newgarden by 0.1179s.
The outing was a night-and-day difference for Penske as a whole compared to Friday’s opening practice when McLaughlin, the defending race winner and polesitter, was 16th and Newgarden was 10th.
Despite spinning 10 minutes into the session, six-time series champion Scott Dixon ended up third overall, with Chip Ganassi Racing entry trailing 0.1269s behind. Graham Rahal quietly asserted his #15 Rahal Letterman Lanigan Racing car in fourth, 0.1538s off McLaughlin’s pace-setter.
Championship leader Alex Palou (Ganassi) came across in the final spot of the top five, 0.2114s behind.
Rinus VeeKay (Ed Carpenter Racing), rookie Marcus Armstrong (Chip Ganassi Racing), Christian Lundgaard (Rahal Letterman Lanigan Racing) finished up sixth through eighth respectively. The Arrow McLaren duo of Pato O’Ward and Felix Rosenqvist rounded out the rest of the top 10.
Source: Autosport