Rast was due to continue his relationship with Audi for a number of years and already had a deal in place for the 2023 season, but was released from contract to pursue other opportunities following the Ingolstadt-based marque’s decision to scrap the LMDh project that he was leading.
The 35-year-old will now compete with BMW in 2023, while also returning to Formula E with McLaren after a single full season with Audi in 2020-21.
Rast said he will fondly remember his time with Audi and the success they achieved together, adding he will be “grateful” for the role it played in establishing his credentials.
“I'm a driver who I am now because of Audi Sport,” explained Rast after finishing second in the Hockenheim DTM finale last weekend which cemented his third position in the standings.
“They provided me with the car and the teams to win championships, especially three DTM championships but also lots of other cool races, Daytona [in 2012], Spa [2012 and 2014] and Nurburgring [also 2014] we won together.
“I always enjoyed working with everybody, in the factory, at the teams, very thankful for the 10-12 years in the end. So yeah, it has been a good time.
Insight: The traits that made Rast and Muller Audi's DTM standouts in 2022
“Obviously I would have loved to put a fourth one on the CV as well, a fourth [DTM] title.
“Very grateful for what Audi has done for me, for my career. So yeah, everything comes to an end at one point.
“I was prepared for this moment and we finished it off in the best manner we could do.”
Rast admitted that he got emotional during his final appearance with Audi at Hockenheim, but had mentally prepared himself for what has been an amicable departure from the manufacturer.
“It definitely was an emotional weekend,” he said.
“There were many occasions where I was thinking about it, especially in the morning in qualifying and also jumping into the car the last time in the race.
“But I was able to prepare myself for that scenario, so it wasn't that hard. But still I had to fight many times.“
Following his success with Audi in GT3 racing, also claiming the ADAC GT Masters title in 2014 season, Rast won the DTM title at his first attempt in 2017 and added a further two titles at the end of the Class 1 era in 2019 and 2020.
Returning to the series this year after his season in Formula E, he scored a 25th career win at Imola and added a further six podium finishes to reach a final tally of 46 in just five seasons of racing, making him the most successful Audi driver ever to compete in the series.
Asked to single out his favourite memory from his stint with the German manufacturer, Rast said he will forever remember the moments that followed his first DTM title success in 2017 when he pipped marque stablemates Mattias Ekstrom and Jamie Green.
“Crossing the start/finish line in 2017 I would say [is my Audi highlight],” said Rast. “For sure that was a rollercoaster moment.
“In '17 in the DTM final Marco [Wittmann] won. He crossed in front of me, I finished second and I expected everybody to be screaming and shouting like 'yay, you won the championship'.
“But it was dead quiet and nobody said anything. And I was like, 'We lost the championship just now'.
“So I was like, 'What happened?' Because I was kind of sure that we were going to be champion.
“Then it took like 10 or 15 seconds. That moment obviously is in my memory forever and I think it's the special moment I have with Audi.”
