Andy Williams and Jon Obika found the net for the visitors while a goal in injury time set up a grandstand finish but Swindon held on to register a crucial away-day victory.
Mark Cooper made just one change to the side that had claimed victory on Derby Day a week earlier, with Andy Williams replacing Michael Smith in attack. After representing their respective nations in mid-week, there were places alongside Smith for Massimo Luongo and Yaser Kasim on the bench.
Ben Gladwin had Town’s best chance of the opening exchanges, smacking a shot against the foot of the upright, while Louis Thompson dragged wide of goal. Swindon continued in that vein for the majority of the half: Jon Obika skewed a shot over the bar after some neat, patient build-up from the visitors.
Wes Foderingham had to be alert to push Nathaniel Mendez-Laing’s shot away from goal in the visitors’ best chance of the half.
On the half-hour, Swindon’s pressure told when Andy Williams gave them the lead. Harry Toffolo’s good work on the left was rewarded as Williams turned his low cross into the back of the net via the post.
Just 90 seconds into the second half, Town doubled their lead. Ben Gladwin’s superbly-struck free-kick from the right picked out Obika in the box and the striker had the simplest of tasks to head home from close range.
Swindon then set about turning the screw and dominated possession for the early part of the second half. Jack Stephens, playing in an advanced midfield role as he had done against Bristol City, strode forward and drove an effort just wide of goal.
At the other end, having dealt easily with a pair of well-struck efforts, Town were opened up midway through the second half. A ball across the box missed everyone in the area and came to substitute Conor Washington who was arriving at the far post. The substitute somehow hit the crossbar with his header with the goal at his mercy.
Luongo and Kasim both made appearances of the bench late on before Posh gave themselves a foothold in the game in injury time. Newell’s low effort whistled across Foderingham and found the bottom corner.
Despite a late rally from the home side, Town held on to register all three points.