BRIAN REID shuffled the pack but was left staring the same old problems as ten man Ayr crashed to their fourth defeat on the spin.
A red card for Gareth Wardlaw after only 15 minutes left United up against it and and once Peterhead nosed in front, the result was never in doubt.
Now Ayr are facing a striking crisis for Saturday's visit of Raith Rovers with Wardlaw and Alex Williams both ruled out through suspensions.
Wardlaw's straight red came on the say so of a linesman after referee Stuart McDonald missed his off the ball retaliation on Stuart MacKay.
The Blue Toon were unable to make their extra man count before the interval as United's re-shaped formation, with Martyn Campbell playing his first game in nine months, comfortably held on.
Ayr won a flurry of corners at the start of the second-half and carved a couple of good chances.
But they failed to make them count and paid a heavy price as Peterhead struck in 58 minutes.
And yet again, Reid's men conceded from a set piece as Graham Sharp's corner was nodded home by sub Andy Bagshaw who had replaced the injured Martin Bavidge. Ayr's ten now faced an Everest but Peterhead were far from convincing and the outcome was still in the balance as the clock reached the 87th minute.
Then came the pivotal moment as Eddie Forrest rashly brought down Sharp for a penalty which skipper Mann confidently thumped home.
There was more misery to come right on the whistle when Sharp cut the ball back and MacKay drilled home the third from six yards.
Ayr assistant boss Scott McKenzie claimed: “The sending-off changed the game. I thought we were the better team in the second-half but lost goals through schoolboy errors.”
STAR MEN: ***Martyn Campbell; **Eddie Forrest; *Mark McGeown.
PETERHEAD: Kula; Donald, Mann, McDonald, Sharp; Good, Buchan, MacKay, Istead; Sloane (Anderson 68), Bavidge (Bagshaw 36). Unused subs: Bruce, Kozmanski, Cowie; Booked: Mann, Good, Istead.
AYR: McGeown; Forrest, Lowing; Henderson, Campbell, Pettigrew; Stevenson, Robertson (Dunn 80), Weaver (Woodburn 89), Wardlaw, Williams. Unused subs: Vareille, Trialist, Stewart; Booked: Forrest, Williams; Sent off: Wardlaw.
Referee: Stuart McDonald; Crowd: 540.