Scott Dixon led Thursday’s opening one-hour practice for the Mobil 1 Twelve Hours of Sebring, second round of the 2014 TUDOR United SportsCar Championship.

The defending IndyCar Series champion clocked in a flier of 1:52.357 in the No. 02 Chip Ganassi Racing Ford EcoBoost Riley. It’s a car he’ll share with fellow open-wheel stars Tony Kanaan and Sage Karam.

Alex Brundle was second in prototypes and overall at 1:52.858 in the No. 42 OAK Racing Morgan Nissan. Rolex 24 at Daytona winners Action Express Racing were third, with Joao Barbosa at 1:53.404 in the No. 5 Corvette DP.

Jon Bennett led the PC category in the No. 54 CORE autosport entry at 1:55.382. Performance Tech’s No. 38 and RSR Racing’s No. 09 cars completed the top three in class.

In GT Le Mans, the rebuilt No. 62 Risi Competizione Ferrari F458 Italia was fastest out of the box with Matteo Malucelli at 1:59.394.

Malucelli, back in this car after testing Krohn Racing’s similar Ferrari at February’s Winter Test, will co-drive with Giancarlo Fisichella and 2013 GT class pole sitter Gianmaria Bruni.

The two factory Corvette Racing C7.Rs were second and third. Tommy Milner was second in the No. 4 Corvette C7.R at 2:00.027 with Jan Magnussen third in the No. 3 Corvette C7.R at 2:00.111.

The No. 56 BMW Team RLL BMW Z4 GTE was fourth with the premiering No. 17 Team Falken Tire Porsche 911 RSR best of those three cars in fifth.

Four different manufacturers made up the top five in GT Daytona, with James Davison leading the way in the No. 007 TRG-AMR Aston Martin Vantage at 2:03.762.

Kuba Giermaziak was second in the No. 30 MOMO NGT Motorsport Porsche 911 GT America at 2:03.800 and Craig Stanton third in the No. 73 Park Place Motorsports Porsche 911 GT America at 2:04.503.

The No. 51 Spirit of Race Ferrari 458 Italia GT3 and No. 45 Flying Lizard Motorsports Audi R8 LMS completed the top five in class.

No red flags interrupted the session, which ran under clear skies with ambient temperature of 59 degrees and track temps of 65.

Second practice occurs at 4:05 p.m. ET, with night practice beginning at 8:00 p.m. ET.

RESULTS: Session 1