Elite Motorsport's Finn Harrison set the pace in qualifying at Donington Park, with his last lap being enough to pip Arden's Leon Wilson to pole by just over a tenth of a second.
Harrison also topped the second fastest charts, earning a double pole position in the East Midlands.
As damp conditions gradually improved, the British youngster repeatedly put his car at the top of the times, only to be knocked off. But on his final lap, he managed to find just enough to usurp Wilson, who briefly looked on course to take a maiden single-seater pole.
Away from the top-two, Fortec's championship leader Linus Granfors was third, but almost four tenths away from Wilson, and a quarter of a second clear of the second Elite car of Alisha Palmowski, who ran in her teammate's wheeltracks for much of the final portion of the 15-minute session.
KMR Sport's Lucas Blakeley fell victim to track limits transgressions in the first half of qualifying, but pieced laps together towards the end to claim fifth, 0.031s ahead of Graham Brunton Racing's Callum Baxter.
Fox Motorsport's Branden Templeton was seventh quickest, ahead of the second KMR car of Chloe Grant, who claimed her best qualifying results since Silverstone towards the start of the year.
Her championship-challenging teammate Harry Burgoyne and Elite Motorsport's newcomer Nickolas Ellis completed the top-10.
On the second fastest times, Harrison again was quickest, this time ahead of Granfors, with Wilson dropping to third. Palmowski, Blakeley and Baxter complete the top-six, ahead of Templeton, Grant, Burgoyne and Ellis.
The first race of the weekend is due to commence at 17.55.
GB4 Championship, partnered by the BRDC, Donington Park provisional qualifying result:
1. Finn Harrison, Elite Motorsport, 1m38.929s
2. Leon Wilson, Arden Motorsport, +0.147s
3. Linus Granfors, Fortec Motorsport, +0.555s
4. Alisha Palmowski, Elite Motorsport, +0.781s
5. Lucas Blakeley, KMR Sport, +1.082s
6. Callum Baxter, Graham Brunton Racing, +1.113s
7. Branden Templeton, Fox Motorsport, +1.249s
8. Chloe Grant, KMR Sport, +1.702s
9. Harry Burgoyne, KMR Sport, +1.798s
10. Nickolas Ellis, Elite Motorsport, +2.431s
11. Megan Bruce, Fox Motorsport, +2.683s
12. Dan Hickey, Fortec Motorsport, +2.957s
13. Jack Taylor, Fortec Motorsport, +3.014s
14. Aleksander Mizera, Idola Motorsport, +3.633s
15. Ava Dobson, VRD Racing, +9.645s
GB4 Championship, partnered by the BRDC, Donington Park qualifying second fastest times:
1. Finn Harrison, Elite Motorsport, 1m39.108s
2. Linus Granfors, Fortec Motorsport, +0.522s
3. Leon Wilson, Arden Motorsport, +0.629s
4. Alisha Palmowski, Elite Motorsport, +0.844s
5. Lucas Blakeley, KMR Sport, +0.936s
6. Callum Baxter, Graham Brunton Racing, +0.960s
7. Branden Templeton, Fox Motorsport, +1.424s
8. Chloe Grant, KMR Sport, +1.691s
9. Harry Burgoyne, KMR Sport, +1.771s
10. Nickolas Ellis, Elite Motorsport, +2.721s
11. Megan Bruce, Fox Motorsport, +2.891s
12. Dan Hickey, Fortec Motorsport, +3.164s
13. Jack Taylor, Fortec Motorsport, +3.211s
14. Aleksander Mizera, Idola Motorsport, +3.740s
15. Ava Dobson, VRD Racing
