Docker, riding in his tenth Paris-Roubaix, was caught up in the first crash of the race only 200m from the start.
The Victorian got back in the saddle and attempted to finish the race but after enduring the gruelling 2.3km Arenberg Forest sector of the race was forced to call time on the race.
“When I was going across Arenberg Forest, I was happy this is the last time I will do Arenberg. I was in a bad way and it’s just so brutally hard,” said Docker.
“It was good to do it one last time and just to be broken by the end.”
Docker's participation in this year's Paris-Roubaix marked a miraculous achievement in itself for the 35-year-old after he suffered a broken elbow during the Benelux Tour less than a month ago.
The Colourful EF-Education Nippo rider had plenty of support going into the final race of his career with fans painting his name on the road approaching the Arenberg Forest, the site of his horrific crash in 2016.
Docker first took part in the Paris-Roubaix in 2009 while riding with Skil-Shimano and claimed his best-ever finish in 2011 when he came home in 15th.