Danny Buchan fended off a hard-charging Josh Brookes to lead the final Bennetts British Superbike practice by less than a hundredth of a second.
The FS-3 Kawasaki rider controlled the entire session from start to finish and held off Be Wiser Ducati's Australian by a mere 0.008s ahead of this afternoon's qualifying.
It was a difficult start to the session for Xavi Fores, who dumped his Honda Racing machine at the Chicane as the Spaniard then had to limp the Fireblade back to the paddock.
But moments later, marshals threw red flags for JG Speedfit Kawasaki rider Ben Currie's crash up at Chris Curve as the orange army was forced to rebuild the soft barriers.
When action got back underway, Buchan shot straight into the 1'27s as he hit the top of the times with Redding in tow, but it wasn't long before Buchan dropped his time to a 1'27.018 as Smiths Racing's Peter Hickman jumped up to second before Andrew Irwin pipped him for the runner-up spot.
Just after Team WD40 Kawasaki's Claudio Corti hit the deck at Charlie's, riders had another halt for debris on the track where the Italian had crashed.
Yesterday's quickest man Josh Brookes clocked a 1'27.732 to nudge Irwin back to third, but moments later RAF Regular and Reserves Kawasaki's Ryan Vickers shot ahead of the Aussie to take over second, just over half a second short of Buchan's leading time.
The front-running Essex rider knocked a tenth off his time to break the 1'26 barrier with a 1'26.907 with just 20 minutes to go and while Irwin moved back up into second, he was still 0.537s off the top spot.
With just six minutes to go, Tyco BMW's Christian Iddon jumped up to fourth with a 1'27.606 while Dan Linfoot moved into the top 10 with a 1'27.916 to slot into eighth, and while Andrew Irwin looked to be making a charge for the top, he crashed at Mansfield after clocking a quick first sector.
Buchan clocked a 1'26.765 to bolster his lead, but with three minutes to go, Tyco new-boy Glenn Irwin laid down a 1'27.245 to move into second spot while Brookes followed him up the order to tuck into third with Oxford Ducati's Tommy Bridewell just 0.037s adrift in fourth.
Brookes finally broke the 1'26 barrier as he set a time just 0.008s off Buchan's best with just over a minute to go, but there was no time for the former champ to make another charge and he had to settle for second as the chequered flag waved.
Yesterday's wet session leader Bridewell stuck in a late flyer to go third quickest ahead of Glenn Irwin and McAMS Yamaha's top man Jason O'Halloran, who rounded out the top five.
Former GP man Redding also made a late charge to stick in a hot lap just seconds before the flag as he went sixth quickest with Iddon just behind.
Honda's Andrew Irwin, Superbike rookie Vickers and roads star Hickman completed the top 10.
