Even more astonishing was the fact that they kept their first clean sheet in 25 games, a leaky defensive run that started last September.
There were also rumours that a large-scale half-time protest would be staged against the Palace chairman, Mark Goldberg, and the way he has run the club, with the supposed relaunch for promotion to the Premiership becoming an increasingly dogged fight against dropping into the relegation zone. Palace are now in such dire financial straits that the Professional Footballers' Association are about to step in to start paying the players, and many of the back-room staff are still waiting for wages.
As it turned out there was no protest worthy of the name, only a couple of banners and a handful of disgruntled fans holding up tiny pieces of paper saying: "Goldberg out". By the end, they were part of the debris being swept across the pitch by a gusty wind that, along with a bobbly pitch, stopped the game from flowing and made life difficult for both sets of players.
But the beleaguered Palace manager, Steve Coppell, was smiling for a change as Mullins' third goal of the season saw the club move up four places to 14th in the First Division. He said: "It was tremendous to win because we had all the excuses with the wind, pitch and not being paid. It was a horrible, scrappy victory but worth its weight in gold. It was a terrific professional job and a morale boost."
Not that Coppell was letting this win go to his head, adding afterwards: "We won't get carried away. There 's a lot to do before we're clear of relegation."
The goal came from the only shot on target in an untidy first half, as Craig Foster slipped the ball on to Mullins inside the area and the England Under-21 prospect tucked the ball past Tony Bullock, a goal that the Barnsley manager, John Hendrie, felt his goalkeeper could have prevented.
Yet while Palace attempted to play something resembling a decent passing game, their opponents failed utterly to come to terms with the conditions, and their hopes of winning this match were further hit by three injuries during the game, as Adie Moses went off with stitches, Darren Sheridan fractured his jaw while Matt Appleby has a suspected fractured pelvis, an injury Hendrie blamed in part on the state of the pitch. And Hendrie did not spare the rod as he accused several of his players of not working hard enough, singling out his strike pair of Mike Sheron and Bruce Dyer for special criticism.
Goal: Mullins (24) 1-0.
Crystal Palace: (3-5-2): Miller; Petric, Linighan, Moore; Smith, Thomson (Evans, 63), Mullins, Jihai, Foster; Morrison, Zhiyi (McKenzie, 73) Substitute not used: Curcic.
Barnsley (3-5-2): T Bullock; De Zeeuw, Moses (Appleby, 35; M Bullock, 43), Jones; Eaden, Sheridan (Goodman, h-t), Richardson, Hignett, Blackmore; Sheron, Dyer.
Referee: M Halsey (Hertfordshire).
Bookings: Barnsley: Hignett, Eaden.
Man of the match: Fan Zhiyi.