The Victorian started the day as the overall leader and was eighth in the road order, which should have been highly favourable so far as navigation was concerned.
However, rather than extending his margin or at least maintaining top spot, he slumped to eighth overall at 17:50s off the pace after setting only the 21st-fastest stage time.
Sanders had expressed concern after Stage 4 about his arms and the elbow which he fractured during Dakar 2022, after which he had not ridden competitively until the Prologue for the 2023 event.
However, his troubles were caused by illness, and he was examined by the medical team at the bivuoac.
“It's been a bit of a struggle today to say the least,” admitted the 28-year-old.
“When I woke up, I didn't feel good at all. I had no energy, couldn't really eat or drink anything, so it seems like I've picked up some kind of bug, I guess. So yeah, it's a bit of a bummer after starting the rally so well.
“What made things even tougher was that my bike is set up to work at higher speeds and I just didn't have the pace I needed today.
“So we'll make a few changes ahead of tomorrow to dial the comfort back in and hopefully with some rest I can be back fighting up front again.”