Just moments after the restart, Lewes' Emily Kraft suffered a serious-looking injury which saw play stopped for 12 minutes.
When play did resume, Palace went a bit of a battle as they struggled to get the ball out of the defensive half; however, they managed to find their way out of it, as Sharpe took hold of the ball and bolted straight for the goal. At the very last moment, before she was about to take her chance, Lewes swooped in and blocked the ball.
Into the final 20 minutes, and while the visitors came close with one long-distance effort, Palace found a better foothold and began to dominate, Everett and Hughes both going close.
A quarter-of-an-hour was added for injury-time, but with Lewes pushing forward, Palace's Player of the Month, goalkeeper Fran Kitching, continued to sweep up any through balls which came her way.
Deep into injury time, forward Rianna Dean - who had only been on the pitch for 10 minutes - rounded off a fine afternoon for Palace, firing home a fourth from close range to see Palace finish at home in strong fashion.
For the final week of the season, the sixth-placed Eagles will travel to fourth-placed Charlton, knowing that a win could see them finish fifth - depending also on Southampton's result at home to Sheffield United.
Palace: Kitching (GK), Gibbons, Everett, Johnson (c), Olding (Guyatt, 90+1), Filbey, Haines, Sharpe (Bailey-Gayle, 90+1), Blanchard, Doran, Hughes (Dean, 84)
Subs not used: Negri
Lewes: Whitehouse (GK), Mason, Cleverly(c) (Thompson, 90), Hazard, Wardlaw (Copus-Brown, 90+18), Palmer, Kraft (Mushtaq, 58), Howells, Barton, McKenna (Johnson, 90), Weir
Subs not used: Moore, Dalton, Longhurst, Angel, Pursey