In the best of 19-frames first round, the man who has dominated this championship in this decade only secured his victory in the 18th frame as he closed out his gallant opponent, Jason Ferguson, 10-8. It was an almighty fright for Hendry and the epic struggle gripped a packed Crucible on a night when predictability is the usual order.
"If I had lost today it would have been a disaster for me," Hendry said afterwards. "Jason punished every mistake. I don't normally feel vulnerable at this venue, but I was today." Ferguson was "devastated". "I felt I let it slip tonight," he added. "But then Stephen played like a true champion and I cannot take anything away from him."
The prospect of Hendry's demise echoed the first-round defeats Steve Davis and Dennis Taylor had suffered as champions in the Eighties. But an exit for Hendry, who has won all bar one world championship in the Nineties, would have registered an even larger seismic shock.
Stung, no doubt, by the ease with which the other favourites had brushed aside their lesser-rated opponents in the day's sessions - Tony Drago, Peter Ebdon, Dave Harold and Ronnie O'Sullivan all slept on comfortable overnight leads - Hendry struck back quickly at the start of the evening session to recover from the shocking 6-3 deficit at the end of the morning session, taking frames 10 and 11, the latter with a break of 106.
His play at this point was alert and ruthless, as he occupied the table to demoralise his game opponent, trying to snuff out the flames of opposition. Ferguson's first scoring assault of the evening was cut short by a mistake on the black, and Hendry took full advantage to draw level at six frames apiece.
Two solid breaks in the 13th frame gave Hendry his fourth on the trot, taking him into the lead for the first time, a fair measure of the difficulty Ferguson had caused him. Ferguson emphasised this by taking his first frame of the night to draw level at 7-7. But when Hendry took the 15th, Ferguson won the 16th and drew level at 8-8.
The presence in Sheffield of a weekend conference on UFO sightings had alerted us to the possibility of unusual events, but a Hendry defeat at the Crucible seemed to rank on a par with Elvis Presley being discovered alive on the moon.
Nothing in Ferguson's career had prepared us for the boldness of his initial surge. Without a tournament win in his professional career and with six first- round exits this year, Ferguson was quoted at 500-1 to win the championship, while Hendry was offered at odds-on before a ball had been cued in anger.
However, Hendry's error-strewn morning had generated all sorts of planetary activity. His form in this nine-frame session had the Crucible buzzing with a mixture of dread for the champion's security, and enthusiasm for the underdog's resistence. Indeed after one break, with Ferguson 5-2 ahead, Hendry had returned to the auditorium to be greeted by an ominous silence of the sort that Greg Norman now knows all too well, while Ferguson drew genuine applause.
Ferguson took the first frame, conceded a century break (104) to Hendry in the second, then took the next two to establish his credentials. Hendry appeared to be back on course with his second century break (118) - he scored 12 in last year's finals - but the seventh frame, which lasted 33 minutes, had the champion sending out distress signals.
It was unlikely that the presence on the adjacent table of Steve James, the last man to beat him here in 1991, had any effect, but a distinct air of sloppiness crept into Hendry's play.
When Hendry missed a long red in the ninth, Ferguson stepped in calmly to compile an excellent break of 129, to leave him just four frames short of an astonishing victory.
During the afternoon theories abounded about Hendry's poor form, with speculation on his increasing reliance on the fear of defeat to kick-start him.
"He'll get it back tonight, just you wait and see," one sage said. He was right, but not by much.