Mitch Evans narrowly edged out Mattias Laine to finish fastest on the first day of GP3 pre-season testing at Silverstone.
In a morning dominated by heavy clouds and cool temperatures, Evans left it until the final 20 minutes of the session to post a 1m50.276s, enough to put him more than half a second clear of the field.
Second went to Carlin's Antonio Felix da Costa, who had ended GP3's previous test at Barcelona on top.
Manor's Tio Ellinas and Carlin's William Buller were the last two drivers to dip below the 1m51s mark.
Only three drivers managed the feat in the afternoon, with Evans again in the mix.
He could not match team-mate's Laine's 1m50.292s however, which was the second fastest time of the day and ensured Arden occupied the top two slots at the day's close.
Conor Daly (Lotus) posted a 1m50.085s to finish third fastest in the afternoon, with the session being brought to an effective close an hour from the finish when the expected rain finally fell.
British youngster Alice Powell, making her maiden GP3 appearance with Status, finished 22nd and 20th in the respective sessions, and also brought out the day's first red flag when she spun early on at Turn 13.
Ethan Ringel (Atech) brought out the second when he crashed just two laps into the afternoon running.
Morning session: Pos Driver Team Time Gap 1. Mitch Evans MW Arden 1m50.276s 2. Antonio Felix Da Costa Carlin 1m50.854s + 0.578s 3. Tio Ellinas Manor 1m50.942s + 0.666s 4. William Buller Carlin 1m50.951s + 0.675s 5. Marlon Stockinger Status 1m51.097s + 0.821s 6. Alex Brundle Carlin 1m51.119s + 0.843s 7. Robert Visoiu Jenzer 1m51.554s + 1.278s 8. Aaro Vainio Lotus 1m51.656s + 1.380s 9. Matias Laine MW Arden 1m51.672s + 1.396s 10. Kevin Ceccon Ocean 1m51.970s + 1.694s 11. Patric Niederhauser Jenzer 1m52.009s + 1.733s 12. Daniel Abt Lotus 1m52.030s + 1.754s 13. Conor Daly Lotus 1m52.099s + 1.823s 14. David Fumanelli MW Arden 1m52.102s + 1.826s 15. Kotaro Sakurai Status 1m52.979s + 2.703s 16. Fabiano Machado Manor 1m53.422s + 3.146s 17. Dmitry Suranovich Manor 1m53.478s + 3.202s 18. Antonio Spavone Trident 1m53.516s + 3.240s 19. Tamas Pal Kiss Atech 1m53.838s + 3.562s 20. Vicky Piria Trident 1m54.267s + 3.991s 21. Ethan Ringel Atech 1m54.386s + 4.110s 22. Alice Powell Status 1m54.498s + 4.222s 23. Robert Cregan Ocean 1m54.811s + 4.535s 24. John Wartique Atech 1m55.317s + 5.041s 25. Carmen Jorda Ocean 1m57.389s + 7.113s Afternoon session: Pos Driver Team Time Gap 1. Matias Laine MW Arden 1m50.292s 2. Mitch Evans MW Arden 1m50.647s + 0.355s 3. Conor Daly Lotus 1m50.985s + 0.693s 4. William Buller Carlin 1m51.445s + 1.153s 5. Aaro Vainio Lotus 1m51.509s + 1.217s 6. Tio Ellinas Manor 1m51.567s + 1.275s 7. Robert Visoiu Jenzer 1m51.650s + 1.358s 8. Daniel Abt Lotus 1m51.660s + 1.368s 9. Alex Brundle Carlin 1m51.675s + 1.383s 10. Patric Niederhauser Jenzer 1m51.797s + 1.505s 11. Kevin Ceccon Ocean 1m51.893s + 1.601s 12. Antonio Felix Da Costa Carlin 1m51.906s + 1.614s 13. David Fumanelli MW Arden 1m51.918s + 1.626s 14. Marlon Stockinger Status 1m52.043s + 1.751s 15. Fabiano Machado Manor 1m52.187s + 1.895s 16. Tamas Pal Kiss Atech 1m52.343s + 2.051s 17. Antonio Spavone Trident 1m52.707s + 2.415s 18. Dmitry Suranovich Manor 1m52.864s + 2.572s 19. Robert Cregan Ocean 1m53.213s + 2.921s 20. Alice Powell Status 1m53.263s + 2.971s 21. Kotaro Sakurai Status 1m53.511s + 3.219s 22. Vicky Piria Trident 1m54.280s + 3.988s 23. John Wartique Atech 1m54.689s + 4.397s 24. Carmen Jorda Ocean 1m55.669s + 5.377s 25. Ethan Ringel Atech 2m05.819s + 15.527s