Jul.21 (GMM) Markus Winkelhock admits his abortive formula one career is now over.

The 28-year-old German, as a Spyker test driver, made his grand prix debut at the Nurburgring last year - and sensationally led a few laps amid the rain chaos - following the demise of regular racer Christijan Albers.

A lack of sponsorship meant he didn't retain the seat full-time, and Winkelhock - whose late father Manfred contested more than 50 grands prix in the 80s - switched to the German touring car series DTM.

To Spox.com, he admits he is not likely to ever return to the grid.

"It was a great experience, but I am a realist," Winkelhock said. "The DTM is what I am concentrated on for the future. Formula one, for me, is over.

"I am not really too sad about it. I am happy with my situation now. With the experiences and the race I had in formula one, of course it is nice to look back, but with Audi in DTM I'm happier than I was in formula one last year," Winkelhock added.