The goal drew the string out of the contest, and set the tone for a second-half of impressive control and maturity from Palace.
With Pharoah probing in particular for the Saints, Palace’s defenders held firm to deny the hosts much of a sight at goal; Percival, Evertt, Hayley Nolan and Fliss Gibbons shut the door time and time again.
This was perhaps best typified after 63 minutes when the ball twice fell for Jamaica international Atlanta Primus to strike inside the box, but Nolan and Gibbons threw themselves in the way of the ball to prevent her from getting a clean shot away.
Southampton did make more headway in the closing stages; Lucia Kendall’s mis-hit cross sailed over Lambourne’s head and hit the top of the bar on 73 minutes, and then won a free-kick as Palace looked to scramble clear.
Peake’s delivery was placed perfectly between defensive line and goalkeeper, allowing Kendall to sneak in and divert home with an outstretched boot.
The hosts continued the aerial barrage for the remainder of the game, coming closest with four minutes remaining when Primus’ near-post flick was first deflected away by Nolan, before her follow-up slammed against the side-netting.
But for sheer resilience alone, Palace were full value for the points which the referee’s whistle soon confirmed.
With Charlton drawing against Lewes, the Eagles are now once more just three points off the top of the table with a game in hand – and a considerably stronger goal difference to boot.
Palace: Lambourne (GK), Percival, Everett, Nolan, Gibbons, Potter (Arthur, 83), Hopcroft (Filbey, 82), Blanchard (Guyatt, 77), Sharpe (Dennis, 66), Hughes, Atkinson
Subs not used: Negri (GK), Reilly, Sibley, Watson, Larkin
Southampton: Rendell (GK), Peake, Rafferty, Mott, Purfield, Wilkinson (Wynne, 86), Pharoah (Lloyd-Smith, 70), Pike, Kendall, Collett, Primus
Subs not used: Howard (GK), Kraft, Haaland, Nohasiarisoa, Milne