Duval's Open win in 2001 ensures he is invited back as a former champion despite his world ranking plummeting to 2 080 and spending the majority of his time working for television as a golf commentator.
The 47-year-old even started with back-to-back birdies before the wheels began to fall off with a quadruple bogey eight at the fifth.
Disaster truly struck for Duval at the seventh as he lost two balls off the tee and then played the wrong ball, incurring an extra two-shot penalty.
His score was originally recorded as a 13 before being amended after his round had finished.
"David Duval's score on the par five 7th hole has been adjusted to 14 instead of 13. His score for the first round is now 91, 20-over-par," tournament organisers said in a statement.
A triple-bogey seven at 17 ensured the former world number one's score was the highest in a round at the Open since Ian Baker-Finch struck 92 in the opening round at Troon in 1997.
Duval shot 80 in the first round of last year's Open at Carnoustie before withdrawing, but defended his decision to keep returning for the tournament despite his lowly ranking.
"It's not reflective of anything I've been doing it's just one of those God-awful nightmare scenarios," he added on his travails at the seventh.
"Honestly, I stood here starting this week figuring I am playing really well and (if) some things happen I could make top 20. Obviously I'll be in the last place."