Rio Haryanto put Caterham at the top of the timesheets after the second day of GP2 post-season testing at Yas Marina.
The 20-year-old Indonesian, who has competed in GP2 for the past two seasons and tested for the Marussia Formula 1 squad, set his benchmark of 1m49.203s late in the evening session.
That put him just over one tenth of a second clear of 2012 racewinner Jolyon Palmer, who also topped the times for much of the morning for DAMS.
Day one pacesetter Raffaele Marciello, staying with Trident, carried on where he left off by going quickest in that morning session. The European Formula 3 champion improved in the afternoon but had to settle for third overall, some two tenths down on Haryanto. The evening session would again yielded the faster times, although Marciello's morning best would still have been enough for fifth overall.
Formula Renault 3.5 runner-up and McLaren junior Stoffel Vandoorne was fourth fastest for ART, fractions ahead of 2013 GP3 title contender Tio Ellinas, who was testing for MP Motorsport.
Hilmer's Daniel Abt, meanwhile, beat Will Stevens (Caterham) and Johnny Cecotto (Lazarus) to sixth, with just two hundredths of a second covering the trio. Racing Engineering's Andre Negrao and Hilmer's Rene Binder rounded out the top 10.
The day was punctuated by just one red flag, brought out in the evening when Arthur Pic's ART stopped out on track.
The lineup will once again feature several changes for the third and final day. Among the switches, Vandoorne will move to DAMS, Marciello and 2012 GP3 champion Mitch Evans will join Racing Engineering, and GP3 race winner Conor Daly will test for ART.