The England Under-21 winger ran from midway inside his own half before gliding forward and beating Aaron Ramsdale deep into stoppage time before the interval.
It was a first victory in six matches for Roy Hodgson’s Eagles, who rise to 12th in the table ahead of a difficult run of fixtures that includes meetings with the likes of Arsenal, Manchester City and West Ham.
Meanwhile, rock-bottom Sheffield United remain winless with just two points from their opening 17 matches in 2020/21.
Chris Wilder’s side remain 11 adrift of safety, though that gap could yet widen on Saturday depending on Brighton’s result against Wolves.
This weekend get a £10 free bet with Betfair, when you bet £10 on a Same Game Multi on the Premier League.
Terms: Min £10 Same Game Multi bet on any EPL match this Fri- Sun. Free bet valid for 72 hours, awarded at bet settlement. Excludes cashed out bets. T&Cs apply.