Vitaly Janelt came off the bench to head home a stoppage-time equaliser and preserve Brentford's unbeaten run.
The German met Bryan Mbeumo's cross in emphatic fashion moments before the final whistle to deny Crystal Palace a first win of 2023.
It seemed as though another substitute - Palace's Eberachi Eze - had provided the game's decisive moment when he headed the visitors in front in the 69th minute.
But Thomas Frank's side refused to give up and the Bees are now 11 games undefeated in Premier League action thanks to a goal that was also the final touch of a match not lacking in endeavour but variable in quality.