Middlesbrough were swept aside as Tony Mowbray’s promotion hopes suffered another setback – with a sixth defeat in seven Championship matches.
Glenn Murray took his goals tally to 27 for the season with a brace as Crystal Palace maintained their own promotion push in convincing fashion.
The former Brighton forward opened the scoring early on, but missed two more chances to complete a first-half hat-trick as Palace struggled to make their dominance count.
However, just after the interval, Murray set up Peter Ramage to double his side’s advantage before the in-form striker’s spectacular drive and Kevin Phillips’ effort ensured Palace extended their unbeaten league run at Selhurst Park to 15 matches.
Faris Haroun netted a late consolation when Boro were three down and the visitors are clinging on to the final npower Championship play-off place after a fifth consecutive away league defeat.
Boro had the first effort on goal in the fourth minute when on-loan Chelsea midfielder Josh McEachran brought a fine save from Julian Speroni.
But it was Palace who broke the deadlock just five minutes later when Wilfried Zaha, with England manager Roy Hodgson watching on, beat a couple of defenders and delivered a cross that Murray converted from close range.
The Palace pair almost combined again midway through the half, but Murray failed to get a touch to the lively England international’s cross before heading over the top.
The home side’s dominance continued as Damien Delaney fluffed his lines from a well worked corner before George Friend’s excellent tackle denied Murray a clear run on goal.
Stephen Dobbie, signed on loan from Championship rivals Brighton last month, almost opened his Palace account on the half-hour, half-volleying goalkeeper Jason Steele’s clearance just wide from 35 yards.
Boro almost got back on level terms against the run of play, though, with Ramage having to spectacularly clear Haroun’s effort off the line after Speroni was beaten.
McEachran ended the half as he started it with a shot at goal, but this time he fired wide.
Palace finally got their second three minutes after half-time when Murray’s header across goal was taken down on the chest by Ramage, who then hooked the ball into the net.
And things got better for Palace when Murray unleashed a left-foot rocket into the top corner nine minutes later.
Dobbie failed to connect with Murray’s cross before the former Swansea midfielder let Boro off the hook by opting to shoot rather than pass in a promising position.
Boro were restricted to long-range efforts as Speroni saved shots from Andrew Halliday and Mustapha Carayol.
However, they pulled a goal back 10 minutes from time when Haroun took on Ishmael Miller’s flick and slotted under Speroni.
Substitute Phillips’ clever back heel was saved by Steele before the veteran forward got his goal, coolly finishing Zaha’s through-ball in the 84th minute.