Mateta backheeled Palace in front during the first half, but Brighton thought they had secured a deserved point thanks to Joel Veltman – until super sub Benteke fired home a fantastic injury-time volley to win it.
In a first half short of inspiration, Mateta provided a flash of brilliance to put Palace in front.
Jordan Ayew made a strong run down the right flank and sent over a low cross towards Mateta. With his back to goal, the January loan signing quickly adjusted and emphatically backheeled the ball home from seven yards.
Mateta was clearly delighted at scoring his first goal for the Eagles, and celebrated by karate-kicking the corner flag.
Brighton were short of ideas, and Palace defended well to head into the interval in front.
However, the Seagulls started the second half strongly, and were rewarded with Veltman’s first goal for the club.
Pascal Gross’ low shot was blocked by Palace defender Mitchell as he battled inside the box with substitute Danny Welbeck and fell kindly for Holland defender Veltman to sweep home left-footed.
Brighton dominated proceedings afte that as Palace sat deeper and deeper: Vicente Guaita was forced into a great reaction stop during a goalmouth scramble, with Seagulls sub Adam Lallana wasted two glorious chances.
And Brighton were left to rue those misses as Benteke’s stunning injury-time volley sealed three precious points for Palace.