One of four drivers in contention for the title, Hill set the fastest time in the early-morning session aboard his West Surrey Racing BMW 330e M Sport.
Hill was a monstrous 0.273 seconds clear of the opposition around the National Circuit in FP1, and set three laps quicker than the best anyone else managed.
His 57.622s from that running could not be dislodged in FP2, although some came very close.
Hill himself sat atop the times in that lunchtime session before Aron Taylor-Smith went quicker in his Power Maxed Racing Vauxhall Astra with a 57.732s.
The Irish veteran, who had gone third in the opening session, looked set to earn bragging rights in FP2, before his team-mate Andrew Watson went faster still on the final lap.
The Northern Irishman’s 57.633s fell just 0.011s short of Hill’s earlier best, and he and Taylor-Smith completed what PMR team principal Adam Weaver reckons is the team’s first 1-2 in a BTCC session.
Hill was demoted to fourth in FP2 by reigning champion Tom Ingram’s Excelr8 Motorsport Hyundai i30 N, but was happy with progress.
“The car’s feeling great today,” Hill told Autosport. “We’re off to a really good start, with no massive changes – we’re just seeing if we can get a bit more out of it.
“I know Watson went quickest in FP2 but there were no new tyres for ourselves – I’m pretty confident we’ll be there in quali.”
Ingram’s last-gasp improvement finally put his rookie Excelr8 Hyundai team-mate Ronan Pearson in the shade.
Source: Autosport