The mere thought of MacIntosh and his supporters will have Bath in a cold sweat for weeks to come. To state simply that the English champions were beaten 19-6 in the Rhondda rain on Saturday is like describing Sir James Goldsmith as comfortably off; they were hammered so comprehensively that John Hall, their manager, had to go back to 1987 to recall a defeat of comparable proportions.
On that occasion, Jonathan Davies and a rampant Neath side skinned alive the West Countrymen in dank, misty conditions at The Gnoll. MacIntosh, a New Zealander who qualifies for Wales in December, is no Davies - twice the size, half the pace, none of the vision - but he was every bit as influential as Pontypridd took a significant step towards a place in the Heineken European Cup quarter-finals and, simultaneously, put a large question mark over Bath's future in the competition.
Described by his coach, Dennis John, as the most destructive No 8 in Welsh rugby, the man from King Country put in so many seismic tackles in so many areas of the field that his opponents ended the game as nervous wrecks, spilling the ball at the merest contact as they waited for the Big One to arrive. The chief? Lord High Executioner might have been a more accurate nickname.
"I'd like to say the crowd call me `Chief' because I remind them of a Maori warrior," explained MacIntosh, who has broken each of his arms twice as a result of his physical approach and plays with a protector on his right forearm and a metal plate in his left. "Unfortunately, it's because they think I look like the guy in One Flew Over The Cuckoo's Nest." As far as Bath are concerned, a night in a small padded cell with Jack Nicholson would be vastly preferable to another afternoon at Sardis Road.
Every time MacIntosh buried a Bath player in possession, the faithful Phil John would burrow his way into the fray to seize the loose ball. Neil Jenkins, whose tactical kicking held up far better than that of his opposite number, Mike Catt, would then belt a diagonal touchfinder deep into enemy territory. With their lineout in the ascendant, it was relatively straightforward for Pontypridd to maintain their stranglehold.
"We could easily have lost by more," admitted Hall, who was so depressed by what he saw that he could not bring himself to indulge in his customary dressing-room rant.
Had injuries not deprived the visitors of their regular centre partnership of Jeremy Guscott and Phil de Glanville, they might still have been dangerous irrespective of the hiding they were forced to take up front. But Bath are now relying to an almost ridiculous extent on a single area of expertise; their world-class midfield are rustling up haute cuisine behind a pack of forwards who appear incapable of boiling an egg.
The writing was on the wall in six-foot high letters once the rain started to roll in off the hills and, sensing the potential for an upset, the good people of Pontypridd turned up in their thousands to create the sort of electric atmosphere that international touring sides have dreaded down the years.
Outstanding Bath outfits of the recent past would have gone into a huddle, rolled up their sleeves and come out fighting. This time the backbone was missing and the predictable pre-match jokes from the travelling supporters about entering the "Valley of Dearth" fell flat as they saw their team reduced to nothing.
"Pontypridd had all the passion of Welsh sides of old while we were almost clueless," Hall said. "The big tackles they made were very impressive - I've only seen MacIntosh play this once but he's obviously quite something - and just when we needed a huge response from our pack, we didn't get it. Our front five is an area of concern and we'll be addressing it as a matter of urgency. I wouldn't rule out the possibility of buying someone in."
Once the home side hit the lead on six minutes, they seldom looked like losing it. They summoned up an instant reply to Jon Callard's opening penalty, MacIntosh and Mathew Lloyd punching holes in the Bath 22, and though the move looked like breaking down, Jason Lewis ran bravely into the traffic to pull in more tacklers and create enough space for his scrum- half Paul John to dummy over from 15m. Jenkins did the rest with his right boot, adding four penalties to his successful conversion.
Pontypridd: Try Paul John; Conversion Jenkins; Penalties Jenkins 4. Bath: Penalties Callard 2.
Pontypridd: K Morgan; S Enoch, J Lewis, S Lewis, P Ford; N Jenkins (capt), Paul John; N Eynon, Phil John, A Griffiths, G Prosser, M Rowley, M Lloyd, D MacIntosh, M Williams.
Bath: J Callard; J Robinson, M Perry, A Adebayo, J Sleightholme; M Catt, C Harrison; K Yates, G Adams, J Mallett, M Haag, N Redman, R Webster, E Peters, A Robinson (capt).
Referee: J Fleming (Scotland).