Stoke slumped to a fourth Sky Bet Championship defeat in five games after going down 2-1 at home to Birmingham.
The visiting Blues notched an early opener when Scott Hogan pickpocketed a napping Phil Jagielka before slotting home.
A fixture low on quality sparked into life around the hour mark when Harlee Dean nodded in his first goal since April 2021.
The Potters, who have won four of Alex Neil's opening 13 games in charge, attempted to stage a late comeback and gave their local rivals a fright.
Lewis Baker converted from the spot with 15 minutes to play, but John Eustace's side held on as they returned to the top half of the table.
Despite now winning only one of Neil's six home games in charge of Stoke, the hosts started the midlands meeting brighter.
Nick Powell and Baker both tested John Ruddy inside four minutes in a frenetic opening to the game.
However, it was the visitors who snatched the advantage in somewhat surprise circumstances.
The 40-year-old Jagielka was caught dozing by a sprightly Hogan, who skipped clear to notch his third goal in five games and eighth of the season.
Lukas Jutkiewicz, making only his second start of the campaign, then threatened to add an immediate second but he rifled over on the spin.
Birmingham's slender lead almost proved short-lived as Stoke nearly responded with an instant leveller.
Josh Tymon, who scored the winner at Wigan in midweek, had his clean volley spilled by Ruddy, but the veteran stopper mopped up ahead of the onrushing Powell.
As weather conditions worsened in the Potteries, clear-cut chances became a premium as Eustace's outfit preserved their advantage through to the interval.
After the restart, the Potters attempted to stage a comeback and nearly found themselves level inside 50 minutes.
A fierce Tymon delivery wreaked havoc in the Blues' area with Ruddy anonymous, but Ben Wilmot could not convert from close range.
And, despite a flurry of Stoke substitutes, it was the visitors who were the source of the game's second goal shortly after the hour mark.
Manchester United loanee Hannibal Mejbri sent in a deep corner that was met by defender Dean at the far post, sending the travelling 2,615 fans into raptures.
Although Birmingham looked destined to coast towards victory, their midands counterparts were handed a lifeline.
After Delap was felled by Auston Trusty in the area, Baker obliged from 12 yards and rifled his powerful penalty beneath Ruddy.
Stoke, who have failed to score more than once in 10 of Neil's 13 games in the dugout, launched a late onslaught in pursuit of a leveller.
However, the visiting Blues, losers in only one of their last seven games, remained resolute to hold on for another impressive victory.
What the managers said...
Stoke's Alex Neil: "It feels as if I'm on repeat all the time. We can't give the goals away that we did and expect to pick up points at this level. Every time we make an error at the moment, it seems to end up in the back of our net. Our confidence at the moment, for whatever reason, is extremely fragile.
"I don't think Birmingham controlled the match or had many chances throughout the game. I think what we may need to do is not take any risks on the ball. It's not how I'd ideally like to play but arguably this is where we're at."
Birmingham's John Eustace: "I thought it was a really dogged performance and I was really proud of the efforts of the group. The spirit of the boys from minute one was fantastic, and it was a fantastic win. Their attitude has been different class all season. We've been here five months; it was really rock bottom with the atmosphere of the club and how things were going.
"It was so important for me to bring in players who want to play for the club to try and create that connection with the fans. Whatever's happening off the field, we can't control that, but it's so important that my players make the fans proud every time they go out on that pitch."