Oxford United are within one game of reaching the second tier for the first time since the turn of the millennium after toppling Peterborough over two legs to book a date with Bolton at Wembley on May 18.

Cameron Brannagan kept up his hot streak this season to score a penalty in first-half stoppage time to cancel out Josh Knight’s opener for Posh and send Oxford on their way to a steely 1-1 draw on the night.

Des Buckingham’s side travelled to London Road with a slender but valuable 1-0 advantage from the first leg after captain Elliott Moore’s goal at the Kassam Stadium. It meant they could sit back and absorb pressure from Peterborough.

And this victory completes a remarkable first taste of management in England for 39-year-old Buckingham, who has had coaching stints in New Zealand, Australia and India before taking over Oxford when Liam Manning jumped ship earlier in the season.

Posh were the dominant team and had the majority of possession in the opening stages without seriously working goalkeeper Jamie Cumming. Indeed, the goalkeeper often mopped up a deluge of corners – nine in the first half alone.

Brannagan took his tally for the season to 12 goals with his coolly converted strike from 12 yards

But the home side took the lead on 41 minutes and it was the hero of last month’s Wembley win in the Bristol Street Motors final, Harrison Burrows, who created the goal to send London Road into bedlam.

Captain Burrows whipped a venomous and inviting cross towards the back post from a free-kick and defender Knight, who had threatened all night from set-pieces, got on the end of the delivery and volleyed home.

Darren Ferguson was the calmest man in the ground after that goal as the stadium reached a raucous volume. But the mood was soon dampened as Oxford had a rare shot on goal which was handballed by Burrows.

Referee Andrew Kitchen pointed to the spot straight away and Brannagan took his tally for the season to 12 goals with a confidently-dispatched penalty. All of Peterborough’s hard work to forge level in the tie was undone in the blink of an eye.

The second half was a tense affair and Posh continued to push for an equaliser but the Oxford back line defended admirably. Indeed, it was the away side who went the closest after the break as Marcus McGuane dragged a shot wide from 18 yards.

Posh thought they had equalised in the 90th minute but Oxford were saved by a familiar hero in Brannagan when he made a goal-line clearance, before defender Ciaron Brown made several warrior-like headed interventions. Cumming also made a full-stretch save at the death.

But Oxford hung on – just – after several more valiant pieces of defending. Buckingham was calm at first but then shared bear hugs with all of his players and staff. After being an academy player here, victory will taste even sweeter for him.