Tander wasted little time getting up to speed, the four-time Bathurst winner charging to the top with a 2m06.270s on his first run.
That left him on top of the times when the session was red flagged five minutes in after Kurt Kostecki buried his Tickford Mustang in the sand at The Chase.
When the session resumed Tander went quicker again, lowering the benchmark to a hugely impressive 2m04.135s.
That time was quicker than Will Davison went to top the morning session and left Tander a whopping 1.8 seconds clear of the field.
Jamie Whincup narrowed the margin to just over a second a few laps later, before David Russell got down to a 2m04.237s in the #99 Erebus Holden at the half-way point.
They wound up being the two fastest times of the session, nobody able to run down the top two in the second half hour.
Whincup did manage to improve to a 2m04.447s to end up just over three tenths behind his Red Bull Holden teammate in third place.
Jordan Boys was an impressive fourth fastest in the #96 Brad Jones Racing Holden while Matt Campbell, fresh from sealing the IMSA GTD-Pro title in the US, was fifth fastest and best of the Fords with the fifth fastest time int the Grove Mustang.
Tickford's Zane Goddard was sixth fastest and last of the drivers to get under the 2m05s mark.
His Tickford teammate Zak Best was seventh fastest ahead of Fabian Coulthard (Walkinshaw Andretti United), Aaron Seton (Matt Stone Racing) and James Moffat (Tickford Racing).
Bathurst legend Greg Murphy finished the session 22nd in the Erebus wildcard entry with a best time of 2m05.871s.
That was significant as this session was the first time Murphy lapped Mount Panorama faster than his famous Lap of the Gods qualifying effort in 2003.
The Bathurst 1000 action continues tomorrow with two more practice sessions followed by qualifying.
