With seven minutes of the 90 left, Palace were unfortunate to find themselves reduced to ten men after captain Seb Williams’s outstretched challenge on Goremusandu was deemed worthy of a sending off.
That invited further pressure from Southampton, and James Martin blazed over from inside Palace’s box in the 89th minute.
But for all their efforts, there was agony for Palace in third minute of stoppage time, as their defence was eventually breached.
The Saints were awarded a fortuitous penalty after Somade’s clearance deflected onto his hand. Oyekunle slotted the resultant spot kick past Hill, denying the Eagles all three points.
The draw keeps Palace second on 24 points, a point behind the Villans – though Aston Villa now have four games in hand.
Palace will look to bounce back with a win when they next host Reading in the U18 Premier League South.
Southampton: Abbotson (GK), Adjei-Afriyie, Dobson-Ventura, Matthews (Sewell,67), Sheaf, Martin, Bariami (Digaba, HT), Rodella (Oyekunle, HT), Gathercole, Daley, Goremusandu.
Subs not used: Upstell (GK), Myers.
Palace: Hill (GK), King, Benamar (Whyte, 84), Adams-Collman, Somade, Fasida, Drakes-Thomas (Osei, 84), Danaher, Casey (Okoli, 90+1), Williams, Henry.
Subs not used: Mason (GK), Montjen.