Former Tottenham and Chelsea manager Andre Villas-Boas withdrew from his first Dakar Rally after damaging his back during the fourth stage in Peru.
The 40-year-old left his role as coach of Chinese side Shanghai SIPG in November to compete in his first rally.
He was two hours 18 minutes and 50 seconds behind the leader after the third stage but on the next his Toyota Hilux hit a sand dune.
Villas-Boas sustained no broken bones but was taken to hospital for checks.
The Portuguese told BBC Sport his spine and back hurt, "but nothing broken, which was the main worry".
He added: "Unfortunately I can't continue but it's part of the Dakar."
The 40th edition of the 14-stage race is based in Peru, which it last visited in 2013, for the opening five stages, using a route largely comprised of sand dunes, before moving to Bolivia and ending in Argentina on 20 January.
In the motorbike section, Britain's defending champion Sam Sunderland also withdrew on stage four and was taken to hospital with a back injury.
And on Wednesday's stage five, car leader Sebastien Loeb - a nine-time world rally champion - abandoned the race following an injury to co-pilot Daniel Elena when their vehicle hit a crater in the sand dunes.