Retired German racing driver Ralf Schumacher reportedly paid tribute to his older brother and seven-time Formula One (F1) World Champion Michael is currently being treated at Grenoble Hospital after suffering brain trauma in a skiing accident in the French Alps on Dec 29.

According to the German news Web site Focus.de, Ralf participated in the Oschersleben Mercedes event as a guest driver, and on his car were the inspiring words that read "Keep Fighting Michael." The event took place on May 18.

"Even after Ralf Schumacher's official racing career ended in 2012, the 38-year-old drove a race taxi as part of the race in Oschersleben Mercedes," wrote the Web site via online translation. "The inscription on his car "Keep Fighting Michael" for brother and injured motor sports legend Michael Schumacher, of course, has a very special meaning," the Web site further wrote.

Mercedes Motor Sports also tweeted a photo of Ralf in a Deutsche Tourenwagen Masters (DTM) taxi car with the slogan.

Today behind the wheel of the @MercedesBenz @DTM_Int race taxi: Ralf #Schumacher. #Oschersleben #KeepFightingMichael

— Mercedes Motorsport (@mb_msp) May 18, 2014

Ralf has raced for Formula One for a decade, from 1997 to 2007. He switched and joined the Mercedes DTM team in January 2008. He took part in a test held at Estoril Circuit in Portugal, but it was during the 2008 DTM season when he officially started racing for the Mercedes DTM Team. He retired from the motor sport in 2013.

Meanwhile, the updates on Michael's coma condition have stopped. It has been revealed that Michael's manager Sabine Kehm will only provide updates when there are significant changes on the former World Champion's condition.

Oschersleben DTM 2014 Winners

After 44 laps, Christian Veitoris of Mercedes won the race. Autosport.com reported. His final time was one hour, 15 minutes and 28.785 seconds. Behind Veitoris were Audi's Mike Rockenfeller, Audi's Edoardo Mortara, Mercedes' Paul di Resta, and BMW's Augusto Farfus at second, third, fourth, and fifth places, respectively.

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