Sammie Szmodics showed former club Bristol City what they missed out on with a brilliant double but still ended up on the losing side as Peterborough crashed to a 3-2 defeat.
Szmodics joined City from Colchester in the summer of 2019 for a fee in excess of £1m but only made four appearances before being sent out on loan to Posh.
That move then became permanent and Szmodics helped United to promotion from Sky Bet League One last term before choosing a date with his previous club to claim the first Championship goals of his career.
But his double ultimately counted for nothing as City prevailed in a Weston Homes Stadium monsoon thanks to a late Chris Martin winner to bag a fourth away victory of the campaign.
Szmodics broke the deadlock with a stunning strike from 25 yards which curled past City keeper Daniel Bentley in the 22nd minute after he received a short pass inside from Harrison Burrows.
The 26-year-old then brought Posh level with two minutes of an exciting first half remaining when producing an exquisite header past Bentley after being picked out by a Dan Butler cross from the left.
That second Szmodics effort completed a frantic spell of three goals in the space of just nine minutes during which City had turned their initial deficit into a brief advantage courtesy of two defenders who were both opening their Robins’ accounts after arriving at the club in the summer.
Former Oxford man Rob Atkinson towered at the back post to head home a Matty James corner in the 34th minute to level before George Tanner arrived on the scene to fire them ahead.
Tanner, who was drafted in from League Two club Carlisle during the close season, pounced in the 39th minute to cleverly thread a low shot into the far corner after Posh keeper Dai Cornell denied Martin.
After sharing four goals in a breathless opening period, it looked like neither side would strike again in a second half which continued to be played at electric pace.
Posh keeper Cornell made terrific saves from three City headers, denying Joe Williams two minutes after the restart before he twice thwarted Martin.
But those two players had the last laugh in the 85th minute with Williams picking out Martin, who tucked his fourth goal of the season into the bottom corner from just inside the box to earn victory for a City side under the control of assistant boss Curtis Fleming with manager Nigel Pearson absent due to Covid-19.
Posh attempted a late rally to no avail as they remained in the relegation zone with substitute Idris Kanu lobbing wide and fellow replacement Jorge Grant seeing his free-kick kept out by Bentley.