Will Buller set the pace on the second and final day of the GP3 Series' mid-season test at Valencia on Friday.
The 19-year-old Briton took his Carlin-run car to the top of the times during the morning session in 1m26.389 - over 0.3 seconds faster than Matias Laine managed the previous day.
Formula Renault 3.5 racer Nico Muller, who returned to GP3 machinery to help out the Trident squad this week, was less than a tenth of a second slower while Mitch Evans completed the top three for MW Arden.
Evans then topped the afternoon session by a thousandth of a second from Buller, but with times around 1.2s slower than those set in the morning, this made no difference to the overall classification.
Antonio Felix da Costa made it two Carlin cars in the top four, while Tio Ellinas, Patric Niederhauser and championship leader Aaro Vainio followed for the Manor, Jenzer and Lotus teams.
The top 10 was completed by Auto GP champion Kevin Ceccon (Ocean), Daniel Abt (Lotus) and Marlon Stockinger (Status).
With Jenzer's Robert Visoiu missing the day in order to take a school exam, his place was taken by Irishman Gary Thompson. The Japanese F3 regular was 20th in the morning and overall, but improved to sixth in the afternoon session on his first time in a GP3 machine.
The red flags came out twice during the day. The first delay was caused when Trident driver Vicky Piria slid into the gravel within the first 20 minutes - denying her team-mate Muller a chance of improving his early benchmark time.
The later stoppage occurred when Ceccon went straight on into a different gravel trap.
Pos Driver Team Time Gap
1. Will Buller Carlin 1m26.389s
2. Nico Muller Trident 1m26.481s + 0.092s
3. Mitch Evans MW Arden 1m26.543s + 0.154s
4. Antonio Felix da Costa Carlin 1m26.641s + 0.252s
5. Tio Ellinas Manor 1m26.654s + 0.265s
6. Patric Niederhauser Jenzer 1m26.693s + 0.304s
7. Aaro Vainio Lotus 1m26.810s + 0.421s
8. Kevin Ceccon Ocean 1m26.865s + 0.476s
9. Daniel Abt Lotus 1m26.879s + 0.490s
10. Marlon Stockinger Status 1m26.956s + 0.567s
11. David Fumanelli MW Arden 1m27.006s + 0.617s
12. Conor Daly Lotus 1m27.067s + 0.678s
13. Tamas Pal Kiss Atech CRS 1m27.077s + 0.688s
14. Matias Laine MW Arden 1m27.188s + 0.799s
15. Dmitry Suranovich Manor 1m27.645s + 1.256s
16. Antonio Spavone Trident 1m27.825s + 1.436s
17. Vicky Piria Trident 1m27.993s + 1.604s
18. Ethan Ringel Atech CRS 1m28.092s + 1.703s
19. Alice Powell Status 1m28.117s + 1.728s
20. Gary Thompson Jenzer 1m28.318s + 1.929s
21. Samin Gomez Jenzer 1m28.343s + 1.954s
22. John Wartique Atech CRS 1m28.414s + 2.025s
23. Fabiano Machado Manor 1m28.486s + 2.097s
24. Robert Cregan Ocean 1m28.762s + 2.373s
25. Carmen Jorda Ocean 1m29.328s + 2.939s
Pos Driver Team Time Gap
1. Mitch Evans MW Arden 1m27.543s
2. Will Buller Carlin 1m27.544s + 0.001s
3. Marlon Stockinger Status 1m27.566s + 0.023s
4. Tio Ellinas Manor 1m27.853s + 0.310s
5. Patric Niederhauser Jenzer 1m28.164s + 0.621s
6. Gary Thompson Jenzer 1m28.275s + 0.732s
7. David Fumanelli MW Arden 1m28.286s + 0.743s
8. Kevin Ceccon Ocean 1m28.294s + 0.751s
9. Tamas Pal Kiss Atech CRS 1m28.301s + 0.758s
10. Antonio Felix da Costa Carlin 1m28.542s + 0.999s
11. Matias Laine MW Arden 1m28.661s + 1.118s
12. Alice Powell Status 1m28.678s + 1.135s
13. Dmitry Suranovich Manor 1m28.799s + 1.256s
14. Fabiano Machado Manor 1m28.859s + 1.316s
15. Conor Daly Lotus 1m28.905s + 1.362s
16. Aaro Vainio Lotus 1m29.208s + 1.665s
17. John Wartique Atech CRS 1m29.223s + 1.680s
18. Daniel Abt Lotus 1m29.380s + 1.837s
19. Ethan Ringel Atech CRS 1m29.508s + 1.965s
20. Samin Gomez Jenzer 1m29.509s + 1.966s
21. Antonio Spavone Trident 1m29.897s + 2.354s
22. Robert Cregan Ocean 1m30.333s + 2.790s
23. Carmen Jorda Ocean 1m30.916s + 3.373s
24. Vicky Piria Trident 1m30.967s + 3.424s