The accident partially severed his right arm and, despite making a remarkable recovery, he was still left with reduced mobility in his wrist and forearm that prevented an immediate return to single seaters. "I have mixed feelings, I am proud with what I achieved today, but also it shows what I have lost".
And while the 32-year-old, who had emerged as one of F1's rising talents all the way up to his final season in 2010, enjoyed the day, he admitted it "shows what I have lost". It was not obvious after six years, I knew I could get there and I can be satisfied.
After Tuesday's running was complete, Renault posted a series of photos and videos from the team's official Twitter account. Kubica returned to Renault F1 to take part in a private test, where the team revealed he "had the biggest smile on after his 115 laps".
On Tuesday, Kubica was back at the Valencia circuit, this time driving the Lotus E20 from the 2012 F1 season - now a Renault show auto, used by several of its junior drivers. "Renault was the first manufacturer to test me in 2005 and I appreciated this new opportunity".
Meanwhile, Renault sporting director Alan Permane has stressed that the test was a "one-off" to help give something back to him after seeing his career cut short. Robert has changed a bit, he has softened and he no longer insists as much when he has a question about the tiniest detail of the settings of his vehicle!
"It is a tricky thing to jump into an F1 vehicle after six years and it was a great performance from him", Permane said in a statement. We tried to condense a Grand Prix weekend in one day, which was very interesting for him.
"Robert has changed a little, he is more mellow and he wasn't as pushy when asking for every detail about the set-up of the auto!" But his comments and his technical return have all rejuvenated us a few years!
"This was a one-off event for Robert", he confirmed.
Renault reserve driver Sergey Sirotkin is also scheduled to drive the vehicle in Valencia, perhaps to set a benchmark time.