As they sought a long-awaited first trophy since their 1969 Inter-Cities Fairs Cup triumph, and seven decades on from their last FA Cup win, Burn's stunning first half header under the famous arch assured the Blyth-raised defender of his rightful place in United folklore; instant iconic status for a real local hero.
And on his 100th appearance for the club, Isak - who had been denied by an offside call seconds earlier - turned home a second after the break, once more sending Magpies fans into raptures in the capital.
It was a lead they rarely looked like squandering and, though Nick Pope was called upon to save from Curtis Jones before Federico Chiesa's last-gasp consolation, this was a deserved triumph for Eddie Howe and his team who, over the course of one Sunday evening in London, became legendary figures - and secured the club's first ever League Cup.
Amid the weekend's Geordie takeover of London - a city Howe's men are unbeaten in during 2025, having already won at Tottenham Hotspur, Arsenal and West Ham - United supporters descended on Wembley in typically vocal fashion. Club partner Sela's donation of 32,000 scarves made for a stunning pre-match scene as the west end of the ground was transformed into a sea of black and white.
Newcastle probed in the early exchanges of an intriguing tactical battle, with Jacob Murphy picking out a stretching Harvey Barnes in the middle before the former let fly from distance to no avail. Midway through the half, Sandro Tonali tried his luck too, with his strike flashing a yard or two past the upright.
It an attacking sense, all of the moves were made by the Magpies in an excellent first period. Kieran Trippier arrived at the far post after Alexander Isak's header was blocked, but his shot was charged down. From the resulting corner, Bruno Guimarães latched on to Burn's header, but his flick was held by Caoimhín Kelleher in the Reds' goal.
And then, right on 45 minutes, Ibrahima Konaté got in the way of a Barnes shot and United had a corner. Trippier floated it in and arriving from deep, around 12 yards out, was Burn. His header was perfect, arrowed through a crowd and low into the bottom left-hand corner, sparking uncontrollable jubilation in the Newcastle end as fans celebrated the club's first Wembley goal in 26 years. It was a moment for the ages, provided by one of their own.
Liverpool had a sniff of a leveller in stoppage time, with Diogo Jota slicing Luis Díaz's knockdown past the post, but with history beckoning the second half looked finely poised. Joelinton, industrious and aggressive as ever in the middle of the park, stopped Díaz in his tracks as he looked to turn Jota's lay-off goalwards soon after the restart. But back came Newcastle. Isak rolled home from close range after Burn's effort had been parried by Kelleher, but a brief VAR check confirmed Guimarães was in an offside position, ruling out the goal.
The Swedish frontman didn't have to wait much longer for his own iconic moment, though. On 52 minutes, Tino Livramento's cross to the back post was headed down by Murphy into Isak's path. The pair have linked up magnificently all for months now but never more than this. His 58th goal in black and white was as coolly taken as most of his others, swept confidently into a bulging net to give Howe's side a two-goal advantage.
Liverpool responded with urgency. Darwin Núñez and Jones were summoned from the sidelines by Arne Slot and the latter pulled the trigger at the end of a flowing counter-attack, forcing Pope to instinctively throw up an arm to repel the midfielder's firm drive. Joelinton then raced across to deny Andy Robertson, but United retained the upper hand. A fine move of their own saw Barnes square for Isak, who went so close to bagging another, seeing his volley from six yards somehow kept out by Kelleher.
Barnes then opted to square with the goal at his mercy and Murphy curled a low effort wide, while Slot made more alterations, sending on Cody Gakpo, Chiesa and Harvey Elliott. The Reds, coasting towards the Premier League title, toiled as United hassled and harried and pressed and pushed them, stifling their creativity and frustrating them at every turn. They had possession in the final 20 minutes, but they couldn't do much with it, before Chiesa's neat low finish in added time reduced the deficit after a protracted VAR check.
But this, finally, after all the waiting and the agony, was Newcastle United's day. Addressing Magpies supporters ahead of the game in his matchday programme column, Howe wrote about "doing everything within our power to achieve something special together - with you and for you." He and his players did that, and then some. A roar from the west end of Wembley, decades in the making, greeted the final whistle. The long, long wait is over - and the Carabao Cup is coming back to Tyneside.
