Kimi Raikkonen shrugged off the surprise of seeing Sebastian Vettel claim fastest time in the opening session on Valencia's new street circuit to take the field below 1min 40secs and set the pace at the end of day one.
The Finn moved to the head of the timesheets with a 1min 39.477secs best with minutes to go in the second 90-minute outing of the day, but had to withstand concerted attempts to dislodge him before being able to claim overall honours.
Fernando Alonso came closest to toppling the world champion - and what a reaction that would have got in his homeland - but eventually came up 0.020secs shy of the Ferrari driver, with Jenson Button also getting to within a tenth, posting a best of 1min 39.546secs to claim third spot for Honda.
Behind the somewhat surprise leading trio, Felipe Massa, Lewis Hamilton and Heikki Kovalainen provided a more familiar look to the next three spots as times on the previously dusty circuit began to pick up both grip and pace. Seventh-placed Timo Glock also dipped below the 1min 40secs barrier that had been hard to break first time around, while all bar Vettel managed to improve on their first session times, some by a large margin.
Vettel's first session benchmark of 1min 40.496secs proved difficult for the Toro Rosso star to beat, but remained good enough for tenth on the combined timesheet between Nelson Piquet Jr and Giancarlo Fisichella, who had rounded out the top half of the order in session two, along with eighth-placed Robert Kubica.
The second 90 minutes saw greater use of the supersoft Bridgestone tyre, leading to the faster times, but also provided greater thrills and spills as the drivers began to find their limits. Felipe Massa headed the list of 'casualties', and was joined on the list of spinners by the likes of Jarno Trulli, Piquet, Fisichella and Nick Heidfeld, who continued to struggle down in 18th spot.
Eleventh and twelfth on the second session timesheets, Mark Webber and Nico Rosberg could well have been lower had the Australian not spotted an out of control Williams heading his way. Webber had earlier brought up the rear of the field in session one, but Red Bull Racing got its act together second time around, promoting the Australian to twelfth overall, and team-mate David Coulthard to 14th, sandwiching the errant Rosberg.
As RBR rose, Williams dropped back, with Kazuki Nakajima falling to 14th in session two, putting the Japanese ahead of Trulli, Vettel, Adrian Sutil, Heidfeld, Sebastien Bourdais - who also spun - and Rubens Barrichello, who could not replicate team-mate Button's late charge.