Craig Dolby made an impressive introduction on his GP2 Series test debut at Barcelona yesterday by ending the afternoon session as top rookie after setting the eighth fastest time.The 23-year-old Briton, who finished runner-up in the 2009 and '10 Superleague Formula championship, put his experience of powerful single-seaters to good use at the Spanish Grand Prix venue on the first of two consecutive days running with the Arden International outfit.His best effort of 1m31.042s was less than 0.3 seconds shy of the afternoon session's second quickest time after completing just 20 laps throughout the three-hours.Despite the single-make series' car, seen as the final stepping stone before Formula 1, being similar in size to its Superleague counterpart, the significantly increased cornering speed and lightness of the Dallara-built GP2/11 ensured that Dolby spent much of the morning session familiarising himself with its unique characteristics around a circuit that he hadn't visited since 2007.Rather than set headline-grabbing lap times in the best of the early cool conditions which would prove the fastest of the entire day, Dolby instead opted to save both sets of new tyres for the afternoon session having had time to acclimatise fully to his new surroundings. That would prove a wise decision when a puncture compromised his morning's tyre allowance further.Craig Dolby: "Overall it's been a great first day behind the wheel of a GP2 car. Adjusting from four years in Superleague Formula has taken a bit of time but I've made progress on each occasion we've been out on track. There's certainly a lot extra to come tomorrow as I become more comfortable with the car. Most of the guys I'm up against have raced, or at least tested, the car before so it was great to get amongst them and set the eighth fastest time this afternoon."Tomorrow's forecast suggests there could be rain in the morning but if there's a window of dry running I'd like to get out there on new tyres to maximise the best of the faster, cool conditions."