Having been nominated by the Sydney Swans earlier on Friday as a priority academy selection, the midfielder went on to run nine minutes and 18 seconds for the closing event at the combine.
It exceeded the long-standing record of Tom Rischbieth, who ran 9:30 at the 2005 combine.
After being nominated as an academy player ahead of Monday's bidding meeting, the former national 800-metre champion had a strong week at Etihad Stadium, including sharing the best result in the beep test (level 16.1).
Tom Lamb claimed second place in the time-trial with an excellent time of 9:45, while South Australian pair Alex Neal-Bullen and Billy Stretch also performed well.
Nathan Drummond, Daniel McKenzie and Jack Steele also ended their testing with top results to be three of the standouts of the week.
3km time trial (minutes : seconds)
Jack Hiscox 9:18
Tom Lamb 9:45
Alex Neal-Bullen 9:54
Billy Stretch 9:57
Nathan Drummond 9:59
Josh Deluca-Cardillo 10:07
Daniel McKenzie 10:07
Connor Menadue 10:07
Liam Duggan 10:11
Jack Steele 10:11
