Substitute Tom Broadbent and Tyler Smith scored in the dying stages as Swindon fought back from a goal down to overcome rivals Oxford United 2-1 for the first time since 2001.
After a frustrating first-half which saw Matty Taylor put the home side ahead, manager John Sheridan brought on Diallang Jaiyesimi, Jack Payne, Rob Hunt and Broadbent, for Jordan Stevens, Joel Grant, the injured Matheiu Baudry and Paul Caddis in order to inject some freshness and new energy at the Kassam Stadium.
But it was the latter, playing further forward than normal, who made the biggest difference scoring the equaliser and assisting the late winner with a dominant flicked on header.
It was the perfect time and the perfect opposition for the Town to secure their first away win in League One this season, and it was a match which will be talked about for years to come.
The opening 15 minutes resembled a Basketball match, with both sides getting in behind each other’s high lines almost at will.
Matej Kovar was forced into making the first big save of the match, clawing away a clean volley from Matty Taylor at the near post, after a smart training ground set-piece from the home side.
Both sides looked vulnerable on the counter-attack, but it was the Yellows who struck first blood.
Liam Kelly won the ball back high up the pitch and instinctively found Taylor between the lines, and the United number nine scooped over Kovar, who was close to keeping the chance out.
Town were undeterred and a slick free flowing move culminated with Matt Smith forcing a strong save out of Simon Eastwood in the Oxford goal.
Caddis and Matt Smith combined well on the right-hand side, Caddis cut the ball back to the lurking Smith on the edge of the 18 yard box, but the Arsenal loanee’s first time effort was parried away to safety by Eastwood.
A few minutes later, Oxford midfielder Kelly almost turned goal scorer, finding space thirty yards out and trying his luck with a speculative, swerving effort, which Kovar had to fly through the air to tip around the post.
Chances became hard to come by in the closing stages of the first half, but Taylor had a golden chance to double United’s lead just before the interval.
Rob Atkinson got in behind the Town defence and appeared to have put his cross on a plate for Taylor, but his connection was not clean, and it was scuffed wide of the post from four yards.
First-half substitute Jack Payne manoeuvred himself some room on the right-hand side of the penalty area, he connected sweetly with a shot across goal, but a defender in yellow was there to divert the effort for a throw in.
Payne was a menace to the Oxford defence, constantly buzzing around and receiving the ball in-between the midfield and defensive lines constantly.
He also created a good half chance for Akin Odimayo, making room for himself on the right-hand side of the area, floating a cross into a dangerous position, but Odimayo wasn't able to capitalise on the chance.
In the dying stages, Town threw everything at Oxford and eventually found their sought-after equaliser courtesy of another of the Gaffer's substitutes.
A ball into the penalty area, resulted in Matt Smith conjured himself some space in the box and his shot was deflected into the air, for substitute Tom Broadbent to convert from close range with a wonderful, hooked volley.
Swindon were not satisfied with a point and kept on pushing for a victory.
Smith, who was arguably the man of the match, thought he won the game, when he received the ball on the left-hand side of the penalty area from a short corner, but his deflected effort went agonisingly just wide of the post.
Town looked dangerous and in the dying minutes they found a winning goal which will be talked about for years.
Odimayo’s raking, diagonal ball was flicked on by Broadbent to Tyler Smith, who looked to nick it past the onrushing Simon Eastwood and rolled the ball into an empty net.
Town had to stay compact and resolute in the face of wave after wave of Oxford crosses and long balls.
Broadbent made a victory saving block right at the death to keep Swindon ahead, and to help secure a first derby victory since 2001.