Points leader Jack Kennedy pipped Luke Stapleford to the fastest lap of the day to end Friday on top at Brands Hatch.
The Honda Racing UK rider clocked a 1min 27.764sec lap to go 0.166secs clear of Stapleford’s Macadam Triumph Racing machine, as Ben Currie was third.
Eugene McManus improved on his morning performance to move a place higher, ending the day fourth on the ROKiT Haslam Racing Ducati, as Rhys Irwin was third.
In GP2, it was champion Owen Jenner who led the way once again, with his Kramer Racing team-mate Jack Nixon second and Keo Walker third.
And in the Cup class, Adon Davie ended the day quickest, with Cameron Hall second and Tom Tunstall third.
Quattro Group British Supersport& GP2/HEL Supersport Cup, Combined practice:
1. Jack Kennedy (Honda Racing UK) 1min 27.764s
2. Luke Stapleford (Macadam Triumph Racing) +0.166s
3. Ben Currie (Oxford Products Racing Ducati) +0.528s
4. Eugene McManus (ROKiT Haslam Racing) 0.830s
5. Rhys Irwin (Gearlink Kawasaki) +0.918s