With the half-time whistle approaching, Osula broke the deadlock on his 100th senior outing after getting onto the end of Lewis Miley's cross from the right flank before poking the ball beyond Palace goalkeeper Dean Henderson.
Magpies goalkeeper Aaron Ramsdale produced an excellent double-save to prevent the hosts taking the lead after the opening half-hour, pushing away Yeremy Pino's bending effort from the edge of the box before quickly turning away Daniel Muñoz's powerful rebound with his right hand.
Sandro Tonali, Lewis Miley, Malick Thiaw, Tino Livramento, Jacob Murphy and Will Osula all returned to the line-up ahead of facing Oliver Glasner's men, who claimed a 3-0 win against Fiorentina in Thursday's UEFA Conference League quarter-final first leg.
Newcastle will be aiming to complete a league double over the Eagles since the 2013/14 campaign, with United claiming a 2-0 win in January's reverse fixture at St. James' Park following second-half goals from Bruno Guimarães and Thiaw.
Today's clash is the 50th league meeting between the two sides, with the Magpies targeting a first win at Selhurst Park since November 2020 as late strikes from Callum Wilson and Joelinton sealed a 2-0 triumph in South London.
**Newcastle United:** Aaron Ramsdale, Lewis Hall, Sven Botman, Joelinton, Sandro Tonali, Anthony Gordon, Malick Thiaw, Will Osula, Tino Livramento, Jacob Murphy (c), Lewis Miley.
**Subs not used:**Nick Pope, Kieran Trippier, Yoane Wissa, Harvey Barnes, Anthony Elanga, Nick Woltemade, Joe Willock, Dan Burn, Jacob Ramsey.