Force India were left to rue a loss of track time on the second day of testing at Mugello after Paul di Resta was restricted to just 14 laps.

The Scot had been due to run all day for his only day in action but a suspected hydraulic issue led to the team electing to change the hydraulics - while an engine change was also carried out at the same time.

Di Resta therefore was only able to set a timed lap late in the day to end up 13th fastest but will now stay on for half a day of running on Thursday morning before Nico Hulkenberg takes over in the afternoon.

"We had a few issues today which kept us in the garage and meant that we couldn't get through much of our programme," he said. "The guys spent a lot of time changing things on the car just before lunch and I only managed to get back out for a final run at the end of the day.

"You always want more laps, but these things can happen and hopefully we can have a full day of running tomorrow to get through our programme and learn what we need to learn."

Chief Engineer Jakob Andreasen admitted it hadn't been an ideal day for the team but was quick to praise the mechanics for the work carried out in the garage.

"It's never nice to spend so much time sitting in the garage, but we had a few reliability concerns that we needed to resolve before we continued running," he said. "We suspected the issue was related to the hydraulic system of the car so changed that as a precaution. At the same time we chose to make the most of the downtime by bringing forward the engine change, which had been planned for the end of the session.

"It has been a tough day for the guys in the garage, but they did a great job to get the car out for the final half hour and give Paul the chance to complete a handful of laps in preparation for tomorrow. Due to the lack of running for Paul, he will now stay on for half a day tomorrow, before Nico takes over in the afternoon."