Simon Trummer took advantage of a tow from teammate Mitch Evans to set the fastest time in the second GP3 free practice session at Monza.
The MW Arden driver produced a surprise lap to take top spot with 12 seconds left on the clock. He continued to slipstream Evans on a second effort, but was following too close by the end of the lap which cost him time in the final corner.
Trummer's late improvement pushed Tom Dillmann (Addax) back to second after the Frenchman had sat at the head of the field for most of the session. Behind him, Adrian Quaife-Hobbs took third for Manor despite crashing out after just 14 minutes.
The Briton's session came to an end when he was clipped by Lewis Williamson as he was letting the MW Arden driver through into the Parabolica. Williamson misjudged where Quaife-Hobbs was as he tried to retake the racing line before turning into the corner, and his left rear wheel made contact with the Manor driver's right front, sending them both into the gravel. The incident, which was partly caused by confusion in traffic, will be investigated by the stewards.
The other surprise of the session was title contenders and ART Grand Prix teammates Valtteri Bottas and James Calado opting not to take to the track at all.
The pair, who are separated by five points at the top of the standings heading into this weekend's title deciding races, watched with their mechanics from the Ferrari Formula 1 team's pit wall, electing to save tires for later in the weekend.
"We were happy with what we did this morning, and it seems that there is quite a big advantage to new tires here so we thought it was better to save them," Calado explained. "Also, the track temperature was much higher than it will be for qualifying tomorrow and we didn't want to get distracted by making setup changes to suit the hotter conditions."
Pos Driver Team Time Gap
1. Simon Trummer MW Arden 1m45.103s
2. Tom Dillmann Addax 1m45.134s + 0.031s
3. Adrian Quaife-Hobbs Manor 1m45.142s + 0.039s
4. Mitch Evans MW Arden 1m45.245s + 0.142s
5. Gabby Chaves Addax 1m45.282s + 0.179s
6. Richie Stanaway ART 1m45.379s + 0.276s
7. Conor Daly Carlin 1m45.387s + 0.284s
8. Tamas Pal Kiss Tech 1 1m45.415s + 0.312s
9. Nigel Melker RSC Mucke 1m45.447s + 0.344s
10. Lewis Williamson MW Arden 1m45.467s + 0.364s
11. Alexander Sims Status 1m45.638s + 0.535s
12. Vittorio Ghirelli Addax 1m45.658s + 0.555s
13. Antonio Felix da Costa Status 1m45.663s + 0.560s
14. Nico Muller Jenzer 1m45.727s + 0.624s
15. Aaro Vainio Tech 1 1m45.802s + 0.699s
16. Zoel Amberg Atech CRS 1m45.804s + 0.701s
17. Matias Laine Manor 1m45.867s + 0.764s
18. Rio Haryanto Manor 1m45.912s + 0.809s
19. Michael Christensen RSC Mucke 1m46.032s + 0.929s
20. Nick Yelloly Atech CRS 1m46.051s + 0.948s
21. Ivan Lukashevich Status 1m46.098s + 0.995s
22. Marlon Stockinger Atech CRS 1m46.314s + 1.211s
23. Callum MacLeod Carlin 1m46.353s + 1.250s
24. Leonardo Cordeiro Carlin 1m46.446s + 1.343s
25. Maxim Zimin Jenzer 1m46.792s + 1.689s
26. Thomas Hylkema Tech 1 1m46.872s + 1.769s
27. Daniel Mancinelli RSC Mucke 1m46.991s + 1.888s
28. Christophe Hurni Jenzer 1m47.709s + 2.606s
29. Valtteri Bottas ART
30. James Calado ART