Sam Tordoff broke Michael Meadows' Porsche Carrera Cup GB qualifying stranglehold at Oulton Park but the championship leader will start the second race from pole.
Track conditions improved throughout the 30-minute session, and as the times tumbled Team Parker Racing's Tordoff claimed pole for round seven, his best lap eight-tenths of a second inside the existing lap record.
However, Redline Racing driver Meadows made it seven poles from eight races by posting pole for round eight, while Victor Jimenez (Redline/Oman Air) in Pro-Am1 and Tautvydas Barstys (Juta Racing) in Pro-Am2 headed their respective categories.
As the earlier rain cleared and a dry line began to emerge, most drivers began the session on slick tyres and by mid-session the time charts changed constantly. Tordoff saw off the rest however, the only driver to dip below the 1min23s barrier.
“I'm ecstatic,” he said. “We needed this after Thruxton and I knew I had it in me. The circuit was dry apart from water running across at Cascades, but you couldn't afford to go off line.”
Meadows, second-best to Tordoff, ensured the front row round eight would be the other way round as he posted the quickest second-fastest lap.
“Every lap was changing,” he said. “The pace is unbelievable compared to last year when it was fully dry and warm. You've got to be on the front row here.”
Jonas Gelzinis (Juta Racing) and Daniel Lloyd (JD Pierce with Team Parker) were third and fourth fastest and also reversed their positions for round eight. Lloyd was made to push very hard after missing some of the early session when a water pipe detached.
Richard Plant (Team Parker Racing) and Glynn Geddie (Redline Racing) each took a fifth and a sixth place in the very competitive Pro category, with Ben Barker (Parr Motorsport) and Rory Butcher (Celtic Speed) sharing seventh and eighth.
Jimenez ended Ahmad Al Harthy's run of six pole positions from the previous six Pro-Am1 races, as the Spanish driver clinched category pole for both races. Derek Pierce (JD Pierce with Team Parker) and Oly Mortimer (GT Marques) shared second and third in Pro-Am1 and kept points' leader Al Harthy (Redline/Oman Air) back in fourth for both races.
In Pro-Am2, Barstys headed Will Goff (Goff Racing) for both races as the Lithuanian racer tagged onto the tail of the Pro-Am1 times. Goff, however, was frustrated and knew that he could have been quicker after leaving his car on full wet settings as the circuit dried out.