Brendon Hartley says he feels “completely drained” after a packed double-header schedule at Sebring International Raceway that saw the Kiwi score overall podiums in both races.

The two-time FIA World Endurance Champion, in his endurance racing return, finished third overall in both Friday’s 1000 Miles of Sebring and Saturday’s Mobil 1 Twelve Hours of Sebring, driving for SMP Racing and Mustang Sampling Raving, respectively.

Hartley, who was the only driver of the 11 on double-duty to score podium finishes in the two enduros, explained that the fatigue began to set in during the IMSA WeatherTech SportsCar Championship race when he was tasked with a quadruple stint in the Action Express Racing-run Cadillac DPi-V.R.

“I think I’ll be tired tonight, especially after I taste a bit of champagne,” Hartley told Sportscar365 following the 12-hour contest. “I’m going to sleep well tonight.

“The last time I jumped into the car I did four stints, which I didn’t expect I was going to be doing that.

“After yesterday’s race I have to say I was completely drained by the end of the race.

“I probably only [had] four hours’ sleep last night, having such a late night and such an early start this morning.

“Going in the adrenaline kicks in, a couple of Red Bulls and a bit of caffeine. I feel good, it wasn’t until I did the quad at the end that I started suffering.

“I think I did all that I could and I’m really happy to be on two podiums.”

Hartley said the fatigue wasn’t helped by the unfamiliarity of both cars, neither of which he had driven a little over a week ago.

The ex-Toro Rosso Formula 1 driver turned his first laps in SMP’s BR Engineering BR1 AER in last weekend’s WEC test at Sebring, while only experienced the Cadillac DPi for the first time in Thursday’s first WeatherTech Championship practice session.

Nevertheless, he praised the AXR crew and co-drivers Joao Barbosa and Filipe Albuquerque for their performance in the 12-hour race.

“It’s tricky for me in the beginning, hopping into a completely different car, cold tires, and it definitely took me one or two stints just to get my head back into the game, having not much experience in this car at all,” Hartley said.

“I felt really good at the end and was doing everything I could. We didn’t have the pace of the other car, sometimes it’s like that, and both sides of the garage had a completely faultless race.

“No problems in pit stops, no accidents on track, and it’s a double podium for the team which is amazing. I think we all did our best.

“We had a really great race car, very forgiving. I really enjoy driving the Cadillac.”

John Dagys contributed to this report.