Dani Clos insisted it was an 'unbelievable feeling' to hit the track for his first run in an official F1 session after taking over Narain Karthikeyan's HRT for the first practice session of the weekend in Barcelona.

The Spaniard, who has spent recent seasons competing in GP2, joined Pedro de la Rosa in an all-Spanish line-up for the first session and managed a total of 19 laps as the team worked on trying out aerodynamic upgrades introduced for the first race of the season on European soil.

Although an electrical issue hit his car right at the end of the session, Clos declared himself happy with the way his time at the wheel of the car had panned out.

"I'm happy to have got into the car for the first time today, albeit for a short first encounter," he said. "The feeling I had when I left the pits and saw the Spanish crowd, whilst driving for a Spanish team alongside Pedro, was unbelievable.

"It was my first time in the new car and I wasn't 100 per cent comfortable since the car is built for Narain, so I had to adapt. We were able to carry out some aerodynamic work and try out some different things on the car so I'm pleased to have completed my job for the team".

It would turn out to be a more frustrating day for Karthikeyan however when he was unable to set a time in FP2 after the team was unable to resolve the issues that halted Clos at the end of FP1.

"I'm disappointed to have not got any laps under my belt today; it's certainly not how I was aiming to start my weekend in Barcelona," he said. "Tomorrow will be an uphill struggle as we've only got one hour in the morning to get the car ready for qualifying in the afternoon, so we're really going to have to get our heads down and work hard. Hopefully we can make up for the time lost today and turn things around tomorrow."

Karthikeyan's issues meant it was down to de la Rosa to conduct as much running as possible in FP2, with 25 laps in the second session alone as he ended the day with the 25th fastest time.