Sire Du Berlais ground down Dashel Drasher late on in the Paddy Power Stayers' Hurdle as the big-race outsiders fought out a thrilling finish to the Cheltenham Festival's day three feature.
At one stage it looked as if Flooring Porter was about to join the Festival immortals and secure his third straight victory in the race, but his tank emptied quicker than in the previous two years and he was passed heading to the last by Dashel Drasher who set sail for home in the hands of Rex Dingle.
A length to the good jumping the final flight, Jeremy Scott's admirable 10-year-old stuck his head down as the Gordon Elliott-trained pair of Sire Du Berlais and Teahupoo were breathing down his neck.
But while the 5-2 favourite could not get by in the hands of Davy Russell, Dashel Drasher had no answer to the late thrust of the JP McManus-owned 33-1 shot who edged his way to a three-quarters of a length verdict.
Dashel Drasher was a brave second at 40-1 and Teahupoo a further neck back in third - but there was a change to the placings in the stewards' room as it was deemed Dashel Drasher had caused interference at the last that was sufficient to deny Teahupoo second spot.
A runner-up behind Flooring Porter in this in 2021 and also a dual winner of the Pertemps in both 2019 and 2020, the 11-year-old Sire Du Berlais was somewhat the forgotten horse of the race and handed Cullentra House handler Elliott his first victory in this premier staying hurdling contest.
Elliott said: "After a hurdle or two I knew he was in a good rhythm. Of course it's a surprise, but Sire Du Berlais can do that - he's either first or last.
"He stayed on well up the hill in fairness to him and Mark (Walsh) gave him a brilliant ride.
"It's great to win the race. We were beaten a short head in a Grade One yesterday (with Gerri Colombe), but it's a great game and it's great to be here.
"We couldn't get him qualified for the Pertemps Final. It just didn't work out for us with ground one day and he probably didn't look that well handicapped.
"He doesn't do anything too exciting as he minds himself, but that's why he's still going at his age.
"I thought Teahupoo would win. He travelled into it and ran well."