Bristol City fans chanted for the dismissal of manager Nigel Pearson after a goal in each half from Matt Phillips and Brandon Thomas-Asante gave West Brom a 2-0 Championship win at Ashton Gate.
The visitors took a ninth-minute lead when Phillips got behind Zak Vyner to run onto a Conor Townsend through ball and confidently clipped a shot past advancing goalkeeper Max O'Leary.
Substitute Thomas-Asante doubled the advantage after 75 minutes, coolly chipping the out-of-position O'Leary from outside the box after finding another yawning gap in City's fragile defence.
That goal brought loud boos and chants of "We want Pearson out" from home fans, whose team lie perilously close to the drop zone. Albion were well worth the points, gaining an increasing stranglehold in the second half.
City had a great chance to take the lead before Phillips' early strike, Tommy Conway getting behind the Albion defence only for goalkeeper Alex Palmer to smother his shot.
But Albion also looked dangerous from the outset. City have conceded too easily in many home games this season and the same was true with the simplicity of Phillips' goal.
The home side almost equalised after 12 minutes when a right-wing corner glanced off an Albion defender, the ball clipping the crossbar before being cleared.
O'Leary kept his team in the game after 25 minutes when more poor City defending at a corner saw him make a reaction save, Townsend being unable to force home the rebound in a frantic scramble.
Conway was thwarted by Palmer again just before the break, the keeper diving to his left to palm wide a fierce drive.
With City enjoying their best spell, Nahki Wells, Conway and Cameron Pring had shots blocked in a frenzied finish to the opening half.
Albion had the first chance of the second period, Daryl Dike volleying wide at the near post from a Jed Wallace cross.
Pearson had to make a change after 52 minutes when centre-back Andy King went down injured and was replaced by Rob Atkinson, the substitution being greeted with loud cheers from home fans.
Albion were looking the more threatening side and after boss Carlos Corberan had made two changes, Thomas-Asante had a low shot saved by O'Leary on 64 minutes.
City were struggling to create any meaningful chances against a strong Albion back-line.
And, with Robins supporters becoming increasing restless, another Albion substitute, Grady Diangana, had an effort deflected for a corner.
Thomas-Asante's precise finish from a pass by another substitute, Tomas Rogic, doused any remaining Christmas spirit among the City faithful and heaped pressure on the already under-fire Pearson.
Andreas Weimann had an injury-time shot beaten away by Palmer, but it was far too little too late. Diangana had the last chance of the game for Albion, but fired inches wide.
What the managers said...
Bristol City's Nigel Pearson: "The reaction of our fans is part of football. It's an emotional game and they are entitled to their opinion. I have been through it before at other clubs. I know the job I have to do here and always try to keep things in context. I would rather the supporters had a go at me than the players. The important thing is that they stay behind the team.
"The bigger picture is that there are good things going on. As a club, we now have to decide if we can strengthen in January. We may have to trade to do so, with players leaving. The priority is to strengthen the defence. I think we will be fine this season. I was brought in to do a job and effecting change isn't easy. I don't feel let down by the players in any way. We came up against a very good side today."
West Brom's Carlos Corberan: "We deserved the three points and it was an excellent reaction from the players to the defeat by Coventry. In the last 15 minutes of the first half we were not so good, but we organised again for the second half and the team showed good character. The mentality of the players is to work hard and win games. When you run a lot, whether you play well or not, it means you always compete hard.
"One of the strengths of the group is that we have players capable of making a difference from the bench. Brandon did that with his pressing after going on and the quality his goal will add further to his confidence. Alex Palmer is playing with a lot of maturity. He made some key saves today. I never look too far into the future. Today I was looking for a reaction from my team. We learn from the past to compete in the present."