A moment of magic from substitute Michy Batshuayi set up Crystal Palace's second goal for Jeffrey Schlupp in the 2-0 win over Fulham, who became the first side in top-flight history to lose eight successive London derbies.
Belgium striker Batshuayi signed on loan in midweek and made an immediate impact within minutes of coming off the bench late on, turning sharply to fire in a shot which Fulham keeper Sergio Rico could only parry to Schlupp.
He admitted he had only met his new team mates for the first time hours earlier.
"I met my team mates today," he said. "I feel good to be here but I need to train with the team. It's a good start."
The day had begun badly for Claudio Ranieri's side when Cyrus Christie needlessly handled the ball in the area as he challenged Christian Benteke on 25 minutes.
Luka Milivojevic put away the penalty, only Palace's seventh home goal of the season, and they almost got another moments later when Benteke's scissor kick thundered off the crossbar.
Fulham's Rico was by far the busier keeper and did well to beat away a shot that deflected off Denis Odoi as Palace made light of the absence of suspended winger Wilfried Zaha.
Fulham remain the only Premier League side without an away win this season, and are now seven points adrift of 17th-placed Burnley.
"We were in trouble from the beginning but we will continue to be positive, be strong. It's important to be optimistic. We have a target in our mind," Fulham boss Claudio Ranieri said.