The Denmark international, who completed a reported £30million pound switch from south to west London in the summer, gave his former side a first-half lead before Daniel Munoz fired home Palace’s second after 66 minutes.
Former Crystal Palace defender Joachim Andersen scored an own goal as the Eagles secured a 2-0 Premier League victory over Fulham at Craven Cottage.
A cagey opening 20 minutes in west London saw neither side exit first gear, but a cynical yellow-card tackle by Sander Berge against Ismaila Sarr on the break acted as the torch paper for the derby to heat up.
A whipped corner by Will Hughes saw Maxence Lacroix’s leap cloud the vision of his marker and – after the defender missed his header – Andersen did not have time to react as the ball cannoned off him in the six-yard box and past Leno for 1-0.
Palace threw men forward, with full-back Munoz showing great composure as he dummied a left-footed shot, cut out onto his right and rifled his effort into the top-left corner to double their score.
