Lewis Williamson set the pace on the final day of GP3 Series at Estoril on Friday.
Driving for Bamboo Engineering, which only announced its series entry this week, the 23-year-old Briton went fastest in a time of 1m27.675s, almost a second slower than Carlos Sainz Jr's mark from the opening day.
A short spell of rain during the afternoon looked set to leave Toyota Racing Series Nick Cassidy, testing for Manor, as the pacesetter.
But after the rain stopped the track dried out enough to allow 2010 McLaren AUTOSPORT BRDC winner Williamson to jump to the head of the order late in the day. His time was 0.088s faster than MW Arden driver Daniil Kvyat's.
Robert Visoiu made it two Arden cars in the top three while British Formula 3 champion Jack Harvey was next up for ART. Briton Dino Zamparelli (Manor) and Italian David Fumanelli (Trident) were next up.
As was the case on Thursday, the day began with a wet track, although unlike 24 hours earlier, the rain continued to fall for much of the morning, leaving lap times around 15s off the marks that would be achieved later.
Kevin Korjus, driving for another new series entrant, Koiranen GP, was the fastest driver in the wet conditions, almost 0.3s faster than MW Arden man Sainz.
Harvey, Fumanelli, Patrick Kujala, Patric Niederhauser, Alex Fontana and Jimmy Eriksson all caused red flags during the day thanks to a combination of spins and mechanical problems.
Pos Driver Team Time Laps
1. Lewis Williamson Bamboo 1m27.675s 44
2. Daniil Kvyat MW Arden 1m27.763s 46
3. Robert Visoiu MW Arden 1m27.848s 66
4. Jack Harvey ART 1m28.080s 60
5. Dino Zamparelli Manor 1m28.139s 63
6. David Fumanelli Trident 1m28.159s 52
7. Alex Fontana Jenzer 1m28.179s 54
8. Patric Niederhauser Jenzer 1m28.212s 51
9. Facu Regalia ART 1m28.322s 60
10. Kevin Korjus Koiranen 1m28.372s 53
11. Giovanni Venturini Trident 1m28.385s 59
12. Emanuele Zonzini Trident 1m28.459s 57
13. Carlos Sainz Jr MW Arden 1m28.485s 52
14. Nick Cassidy Manor 1m28.522s 74
15. Conor Daly ART 1m28.923s 63
16. Aaro Vainio Koiranen 1m29.044s 74
17. Ethan Ringel Bamboo 1m29.076s 42
18. Nick Yelloly Carlin 1m29.104s 56
19. Patrick Kujala Koiranen 1m29.335s 41
20. Luis Sa Silva Carlin 1m29.341s 75
21. Vicky Piria Manor 1m29.461s 54
22. Josh Webster Status 1m29.648s 52
23. Eric Lichtenstein Carlin 1m29.823s 69
24. Samin Gomez Jenzer 1m30.177s 77
25. Roberto La Rocca Bamboo 1m30.399s 29
26. Melville McKee Status 1m31.780s 37
27. Jimmy Eriksson Status 1m32.761s 38