Minutes after Butt's goal finally gave the St Andrew's faithful their first Premiership home success of the season, Bruce sat in the press box listening to a phone-in as he waited to be interviewed. When a Birmingham fan denounced the overall performance of his one-time Manchester United colleague, it was more than the manager could stand.
Snatching the microphone, Bruce snapped at the startled caller: "You're the only person who thinks that." But then Butt often provokes unlikely responses. Remember how a certain legendary Brazilian nominated him as England's best player at the last World Cup?
With the draw for next year's finals plastered all over the newspapers, and Sir Alex Ferguson's engine-room exposed as humdrum 72 hours earlier, Butt's header was timely in more ways than one. Birmingham were six minutes from another disappointment on their own patch and it left a wretchedly unadventurous Fulham little time to retaliate.
Butt is candid about his lack of impact since arriving on long-term loan from Newcastle. Were the crowd justified in criticising him? "Definitely. They paid good money to come to watch us and they work all week to earn the wages to do that," he said.
Value for money was in short supply. Yet a goal, even one that stemmed from a long, hopeful cross by Jamie Clapham that was headed into Butt's stride by the outstanding Emile Heskey, covers a multitude of sins. Bruce savoured "as big a result as I've had in management" and Birmingham deserved it because, unlike Fulham, they actually tried to win.
In pursuit of the aim, he had abandoned the idea, utopian for a side in Birmingham's predicament, of starting with orthodox wingers. Compact and direct, they pressed for every ball.
"This is a working-class club and will remain so," Bruce explained. "The fans want to see their team play a certain way. I've tried to change that and it's time we went back."
No one wants to see their side play as negatively as Fulham, and Chris Coleman bemoaned their poor attacking display. However, with Brian McBride even more isolated than Heskey, and scant attempt to exploit the weakness of Olivier Tebily or the inexperience of the excellent debutant Marcos Painter at full-back, the manager must take responsibility.
He was lacking two important players, Luis Boa Morte and Papa Bouba Diop, trusting that their return against Blackburn next weekend will reinvigorate Fulham. Their form at Craven Cottage will probably be crucial to their prospects of survival, for this loss left them with an away record of six defeats, three points and no wins: relegation form.
There should be no pressure, Coleman asserted, to sell their assets during next month's transfer window, as they did two seasons ago when Louis Saha left and fourth place became ninth by May. Mention of Saha, Butt and Bruce was a reminder that, intriguingly, Birmingham's last home games of the year are both against United, in the Carling Cup and Premiership.
Before then, they return to Manchester to face City. Bruce was relieved to hear another old colleague, and indeed ex-Fulham player, will not be lying in wait. "Andy Cole is suspended for next Saturday," he beamed, colour returning to his drained cheeks. "Maybe our luck is changing."
Goal: Butt (84) 1-0.
Birmingham City (4-4-1-1): Vaesen; Tebily (Jarosik, 70), Cunningham, Upson, Painter; Johnson, Butt, Clemence, Lazaridis (Pennant, 55); Dunn (Clapham, 75); Heskey. Substitutes not used: Maik Taylor (gk), Pandiani.
Fulham (4-5-1): Crossley; Rosenior, Knight, Goma, Bocanegra; John, Legwinski, Christanval, Malbranque, Radzinski; McBride. Substitutes not used: Warner (gk), Helguson, Elrich, N Jensen, Pearce.
Referee: U Rennie (S Yorkshire).
Man of the match: Heskey.