No.2 Audi R18 'ultra' during practice for the 60th 12 Hours of Sebring (Photo Credit: DPPI)

No.2 Audi R18 'ultra' during practice for the 60th 12 Hours of Sebring (Photo Credit: DPPI)

The trio of Audi R18 ended the first day of official running at Sebring International Raceway comfortably leading the 60 strong field through all three Thursday practice sessions.

The day saw the first 'real' competitive sessions following the build-up through the first part of the week and several open practice sessions for the World Endurance Championship (WEC) and American Le Mans Series (ALMS) entrants for the 60th running of the 12 Hours.

Times fell all day, the fastest laps coming during the night session that rounded out the day. The fastest lap around the 3.74mile airport circuit was completed by Tom Kristensen aboard the no.2 R18 'ultra' he shares with Allan McNish and Dindo Capello in the closing minutes of a  night practice session extended to just over two hours after succession of red flags.

Kristensen's time (1:47.049) was over a second and half faster than the initial time set by Audi teammate Romain Dumas in the morning's first session. Dumas' no.3 car would end the final session third fastest behind the no.1 of Le Mans champions Andre Lotterer, Benoit Treluyer and Marcel Fassler.

The best of the rest was also the best ALMS entry, Muscle Milk Racing chasing the Audi's in all three sessions in their first race with the HPD chassis. Their final session time (1:49.910) was not their best of the day, that coming in the opening session when Klaus Graf ran second Dumas on the timesheets.

The top four in the night practice were a distance clear of another team making their debut in a HPD chassis, with British squad JRM fifth fastest 4.4 seconds off the pace set by Kristensen.

The best time of the day in LMP2 – also set in the night session – went to yet another team using HPD's chassis for the first time, and one of only two American squads in the World Endurance Championship as Frenchman Stephane Sarrazin put Starworks Motorsport's no.44 car clear at the head of the class. The Morgan branded OAK Racing entry was second fastest with Olivier Pla at the wheel. Level 5 Motorsport's no.095 entry – one of two for Scott Tucker's operation was third fastest, the best of the ALMS points scorers.

Split by less than one tenth of a second BMW and Ferrari shared GTE Pro honours. BMW Team RLL's no.56 car carried the ALMS class champions' strong 2011 form into 2012 by setting the pace to end the day. However, it was the AF Corse Ferrari of Giancarlo Fisichella, Gimmi Bruni and Toni Vilander that led the WEC entered  teams as all five WEC GTE Pro combatants (and most of the ten ALMS runners) squeezed into just two seconds of timesheet.

Making incursions into that narrow time bracket were the best of the GTE Am entries, the three Ferrari 458 dominating the class for Luxury Racing, Krohn Racing and AF Corse ahead of the better of Larbre Competition's pair of Corvettes.