Bortolotti became the first repeat winner of 2023 when he beat Abt Audi's Ricardo Feller in a race-long battle at the 4.3km circuit, taking the championship lead in the process.
However, his post-race celebrations were rather tame due to heat exhaustion on a hot day in eastern Germany, with the ambient temperature reaching 30C and temperatures inside his car peaking at 70C.
Images showed SSR Performance mechanics having to pour water and ice cubes over Bortolotti when he returned to the parc ferme. The Italian driver was also seen sipping a can of soft drinks in order to cool himself down after the race.
"I immediately radioed through to the guys: 'Hey, bring me something to drink right away. I want something cold, because I have to get out of the car as quickly as possible,'" Bortolotti told broadcaster ran.de.
"That's why I didn't enjoy the lap after crossing the finish line, which you normally enjoy because that's how you win a race."
Bortolotti also struggled with heat inside the car in Saturday's opening race, where he finished second to Emil Frey Ferrari driver Jack Aitken.
The Lamborghini Huracan is one of the few GT3 cars without air conditioning, and the main cooling system on the latest Evo version is also understood to be worse than the previous model.
"Especially when you roll back to the pits after the race, all the heat comes into the car," he explained. "At that moment it gets pretty hot in the cockpit, but I'm feeling better now.
"In the last laps, I was always asking, 'How many more laps can we do? Luckily everything is fine, but we have to work on the cooling somehow, because it's really hot in the car."
Bortolotti wasn't the only driver to suffer from a lack of cooling in a Lamborghini during the fifth round of the season.
Maximilian Paul, who won on his first outing of the year at the Nurburgring earlier this month and made a second DTM appearance at the Lausitzring, had to retire from both races because of extreme heat.
The Grasser driver parked his car two laps before the finish on Saturday, before having to retire with 11 laps still to run in Sunday's race.
Paul was heard saying "I'm completely exhausted" over team radio shortly before he pulled into the pits in the opening race of the weekend.
A problem with the ventilation system was to blame, with the small cooling duct on his car getting clogged due to dirt from the track.
"I had a problem with the temperature in the cockpit. The ventilation had clogged up and I couldn't get any air, which meant I was pretty beat up and had to stop," he explained.
Feller, whose Audi R8 LMS GT3 is equipped with air-con, had to deal with dirty exhaust fumes coming from Bortolotti's car. The German driver spent nearly the entire race on the tail of the Lamborghini, finishing just under four tenths behind him after 45 laps of racing.
"I didn't really have any breathing problems, but a little fresh air when getting out and before that on the slow-down lap definitely didn't hurt," he said.
"For an hour I was inhaling the full exhaust fumes that come into the car through the ventilation. The exhaust pipes of the Lambo are directly pointed at the person driving behind."
With the exception of the new-for-2022 BMW M4 GT3, using air conditioning normally has a negative impact on engine performance. It's why most drivers from other manufacturers don't normally take advantage of the system.
"We drive without it if possible, because even if the air conditioning costs very little power, of course you try to go as fast as possible in the race," explained Porsche's Thomas Preining.
