The visitors took the lead in the first half as Jason Puncheon drilled a low shot into the bottom corner and were 2-0 up with 20 minutes left in the match as Joe Ledley tapped home a rebound from close range.
Puncheon then added a spectacular third late on, curling the ball into the top corner from the edge of the box to compound Cardiff's misery and leave them with a mountain to climb.
Here, Sports Mole takes an in-depth look at a potentially pivotal 90 minutes in the Welsh capital.
On target: 4
On target: 8
Was the result fair?
Yes. The 3-0 scoreline may be a little generous to Palace, but there is no doubt that the visitors deserved a victory and the accompanying three points. It was a scrappy game with not much goalmouth action, but for once Palace were clinical in the final third and took full advantage of the few opportunities that they did create.
Cardiff, on the other hand, had two chances throughout the entire match, and even they were by no means sitters. They did nowhere near enough to warrant anything from this match and, while the scoreline may be a little harsh on them, they will receive little sympathy from a home support that is getting increasingly restless.
In a season that looks increasingly like ending in disappointment, this may well be the nadir. It was a lacklustre and abject performance from the hosts, who showed none of the fight, determination and desire that was required for a self-confessed must-win game.
They are not the first team that have failed to break this Palace defence down, and they won't be the last, but they never showed any signs of seriously troubling the visitors' goal. Julian Speroni had one save to make in the first half, and that was the closest they came. They were limited to long balls forward and crosses for the majority of the game, and the Palace defence dealt with that easily.
Defensively, things are unravelling. Palace had scored just six goals on their travels all season before today, but they have increased that total by 50% this afternoon. Cardiff, meanwhile, have now conceded 12 goals in their last three games and can't expect to stay up with a record that bad.
Is there any way back for Ole Gunnar Solskjaer's side? With 15 points still to play for, he will believe so, but based on today's performance it would take an unlikely turnaround for them to retain their Premier League status. With West Bromwich Albion and Fulham both winning, this match could well prove to be a fatal blow to their survival hopes.
Crystal Palace's performance
The 3-0 scoreline gives Palace their biggest win of the season so far, but that could apply to the importance of the victory as well as the number of goals scored. The visitors knew that victory today could send them eight points clear with six games to play, while they also have a game in hand over Cardiff.
As it happens, results elsewhere mean that Palace are now seven points clear rather than eight, but that is still a commanding lead and it would be a surprise if Tony Pulis's side fail to add more points before the end of the season having now won back-to-back matches.
As usual, it was not a festival of beautiful football from Palace, but they nullified the threat of Cardiff, soaking up the pressure and possession before hitting them on the break. In many ways it was a repeat of their performance against Chelsea last week, although on this occasion Palace were more clinical in front of goal.
While Solskjaer's appointment at Cardiff is still under question, there can be no doubt that Pulis has turned Palace around. This victory puts him within touching distance of maintaining his proud record of never having been relegated, and it would be a big shock to see them hauled back into the mire now.
Sports Mole's man of the match
Jason Puncheon: He has had his good moments and his bad moments this season, but today's performance will certainly fall into the former category. The winger had two poor shots in the first half but was not put off and gave his side the lead just after the half-hour mark with a crisp finish.
He continued to provide a threat in the second half and capped off a fine victory with a goal fitting of the occasion. His curling effort into the top corner left David Marshall helpless in the Cardiff goal and was a just reward for a good individual display.
Despite such an abject performance from the hosts, there weren't many glaring mistakes that contributed to their defeat. However, the gaffe of the game goes to the marking from the Cardiff defence in the build up to Palace's second goal.
Marouane Chamakh was left completely unmarked from a free kick to nod towards goal and, while Marshall did well to keep the initial effort out, he could only turn the ball into the path of Ledley, who poked home from close range.
Phil Dowd had a fairly quiet game today, with no major decisions to make. A half-hearted appeal for a Cardiff penalty was correctly waved away in an otherwise uneventful game for the ref. One minor criticism would be the number of yellow cards handed out, but none of the decisions were shockers.
Cardiff: Cardiff travel to St Mary's to take on Southampton next Saturday in a match they simply have to win.
Crystal Palace: Palace, meanwhile, could move even closer to survival when they host Aston Villa at Selhurst Park, also on Saturday.