Australia Post attempted to argue a worker's back pain was not caused by hours of overtime spent lifting heavy mail trays, but instead by a "sneezing fit" he'd had while driving.
But the company failed to convince the Administrative Appeals Tribunal that the worsening of the employee's existing spinal condition was not work-related, and is liable to pay compensation.
The worker, who began with the Australian Postal Corporation in 1990, said he injured his back seriously one night at work in June 2012.
He said he had been working two hours of overtime, and was moving trays weighing 10 kilograms or more on to trolleys using a twisting action.
The overtime lasted about two hours longer than his usual shift, and he said he had moved about 100 trays in that time.
Just before he was about to finish, the worker said he felt a sharp pain in his lower back, which lasted for about five to 10 minutes.
He thought it would go away and didn't report it, instead driving home and going to bed.
When he woke, he felt strong pain again, and said "every movement" hurt him.
He returned to work two days later, but could barely walk or stand, and took two more months off, before returning gradually to his job.
Australia Post denied him compensation in July 2013, but later revoked that decision. It then determined the effects of the injury had ceased by November 2013, and the worker took that decision to the tribunal.
At the tribunal, Australia Post first argued the injury had ceased in November 2013, but changed its stance to contend the worker never suffered a work-related aggravation of a degenerative back condition.
It argued the initial notes of his general practitioner were accurate, and appeared to indicate that the worker had said the back pain began that morning, after he had sneezed while he was driving.
A report by the worker's supervisor also suggested he had said the injury was not work-related at first, and had taken two days of normal sick leave.
The company also argued that there was evidence of a longstanding injury dating back to 1999 and pointed to inconsistencies in the worker's version given to different doctors.
However, tribunal senior member Jill Toohey found the work had aggravated an existing spinal condition, and the effects had not ceased in November 2013.
She ruled that he had not suffered the back pain because of a sneezing fit.
"On balance, I am satisfied that [the worker] suffered an aggravation of his previously asymptomatic degenerative disease in his lumbar spine, to which his employment contributed to a significant degree," she wrote.
That makes the worker eligible for compensation.