Willie Mullins looks to have grabbed the British trainers' title with both hands after Macdermott clung on to land the Coral Scottish Grand National Handicap Chase by the narrowest of margins.
Connections of the unexposed six-year-old endured a lengthy wait as the judge pondered the photo finish for some time, but teams Mullins were soon jumping for joy as it was announced Macdermott had got the better of Toby Lawes' Surrey Quest to plunder the valuable handicap under Danny Mullins by the smallest of margins.
The valuable steeplechase provided winning trainer Willie Mullins with an additional £112,540 in prize money, leaving the Closutton-based maestro £163,000 ahead of Dan Skelton and £255,000 clear of Paul Nicholls in the title race.
Paddy Power makes Mullins now 1/50 to land the British jump trainers' title, which concludes at Sandown next Saturday.
The race was not short of early drama with Mullins, who saddled six in his bid to take a stranglehold on the trainers' title, quickly seeing his sextet turn to a quartet after Mr Incredible refused at the first fence and We'llhavewan fell at the same obstacle.
Having been ante-post favourite at one stage for the Scottish staying feature, it was somewhat surprising to see Macdermott sent off an 18/1 chance on his first attempt at the marathon trip. A winner over fences for the first time at Leopardstown earlier in the month, Macdermott travelled strongly in the hands of the Danny Mullins, picking up the running from the well-supported front-runner Mr Vango with four fences to take.
Surrey Quest went off in pursuit in his bid to give Toby Lawes a memorable success and there was nothing to split the pair to the naked eye following a ding-dong battle up the Ayr straight.
However, following a careful examination of the photo from the judge, it was declared that Macdermott had clung on by a nose.
Git Maker finished back in third, with team Mullins earning more valuable prize money as the 50/1 chance Klarc Kent came home in fourth ahead of stablemates Ontheropes and Spanish Harlem.
"I thought we were beaten, but then one of my owners opened up the betting on his app and we were favourite and the second horse was 14-1. The odds changed a bit in their favour, but then the result came out," explained the winning trainer, who later stretched his lead even further in the trainers' championship when saddling both Chosen Witness and Quai De Bourbon to success.
He said on Racing TV: "To me, the way he jumped was spectacular, I'd have no problem aiming him for Aintree next year or for the Irish National, we'll see but we'll be aiming for all those chases.
"He's got age on his side, so it's fantastic. He just got experience every day he went out; we started him off at two miles and just kept running him for the experience because he hasn't got runs under his belt and last year it took me all season to get him fit enough.
"He's a big, lazy fella and he just takes so much training. And he's so laid back, but now he's getting the hang of it and if we can get him in this sort of form, it'll be straight to those kind of staying chases for him to run in."
Mullins, who enjoyed Aintree glory with I Am Maximus last Saturday, added: "We had one go before the first and one fall at the first, then we had two up the front and two out the back, so I said 'well we've both ends of the race covered'.
"The two up front finished first and fourth and Spanish Harlem came on to be sixth, so he ran a great race and there's going to be a good race in him too.
"The sun's out, it's a fantastic crowd and it's just turned out to be an amazing day."
In regards to the trainers' title, which Mullins now firmly has 'one hand' on, he said: "I'd say we've a bit to go yet, there's still a lot of prize-money to play for, but we're in pole position and it looks very good."
