Five-time race winner Glock made a highly-anticipated return to the DTM last weekend as a wildcard, driving a BMW M4 GT3 entered by 1989 champion Roberto Ravaglia's Ceccato Racing team.
Qualifying 18th out of 28 drivers for the opening half of the double header, Glock's race lasted only a single lap after he was hit multiple times by Mercedes driver Mikael Grenier as they went side-by-side through Acque Minerali - before receiving another smack from Esteban Muth's BMW at Rivazza.
The damage to his car was so significant that it broke the suspension and Glock had to peel into the pits at the end of the lap to retire from the race.
Speaking in the immediate aftermath of the incident to TV reporters, Glock described Grenier's actions as "more than stupid", questioning why the DTM rookie was so aggressive while running outside points-paying positions.
"He's just a complete idiot, Grenier, or whatever his name is," said the German driver. "He ran into my car 13 times for no reason, sometimes on the straight.
"From the start on, Mikael Grenier was just driving into my car. I don't know what his plan was. But he was on the straight bouncing into my car until my suspension was broken and then I had to slow down and then one of the other guys just drove into me because he couldn't avoid me.
"I mean the way he acted on lap 1 fighting for P18, I don't get it. It's more than stupid to be honest."
For the second part of the weekend, Glock set an excellent lap in qualifying that was only eight tenths shy of Abt Audi driver Ricardo Feller's pole time - although such was the competitiveness of the grid that he could only take the start from 18th place.
Glock made steady progress through the 33-lap race and crossed the finishing line in a respectable 11th place, just under two seconds behind the final-points scoring car of Mirko Bortolotti.
However, the German driver felt he had the pace to break inside the top 10, having lost a significant chunk of time with a slow pitstop at the end of lap 5.
The Ceccato team, which has no experience of tyre pitstops from its time in Italian GT, lowered his BMW before the front-right tyre was fully attached - which meant the car had to be put back on jacks to secure the wheel in its place.
"Sixth or seventh place was possible, but I'm glad that I made it to the finish this time," said Glock.
"Unfortunately we had a really bad pit stop. That's when everything went wrong and we lost eight seconds. I came in behind Marco [Wittmann] and then dropped back."
Glock nevertheless took satisfaction with his guest outing in the DTM, having kept a lid on his expectations coming into the weekend.
Both Glock and the Ceccato team had zero experience of running the Michelin tyre on the BMW M4 GT3 prior to their DTM foray last weekend, with Pirelli the sole supplier for the Italian GT championship.
"I had a lot of touches again on the first lap," said Glock. "So I'm happy for the team that we finished eleventh.
"Our lack of experience was particularly evident in the qualifying sessions, where we simply couldn't get the best out of the tyres that were new to us. We would need more test time for that.
"It was important to see what the level in the DTM is like [for the team]. I had a lot of fun this weekend and really enjoyed my mini-comeback in the DTM."
Glock will spend the rest of the year competing in the Italian GT championship with Ceccato, having already picked up a win at Monza along with teammate Jens Klingmann.
Glock expressed his desire to return to the DTM full-time in 2023 with Ceccato in the lead up to the Imola race, but Ravaglia stressed that the outing was a one-off for now.
