Osimhen, the Italian league's top scorer with 21 goals, had missed Napoli's previous three games with an injury to his left leg.
He came on in the second half and immediately lifted the home side with a shot that hit the crossbar.
“Osimhen is a fan favourite, so when he comes on there's always a wave of enthusiasm for the entire squad,” Napoli coach Luciano Spalletti said.
Napoli sorely missed Osimhen in a 1-0 loss to AC Milan in the first leg of the Champions League quarter-finals on Wednesday. He will start next week's return game, Spalletti said.
The other significant bit of news for Napoli occurred before kick-off, when club president Aurelio De Laurentiis met with hard-core 'ultra' fans, who had been protesting over high ticket prices and new rules governing flags and banners inside the stadium.
After the nearly two-hour meeting inside the Stadio Diego Armando Maradona, De Laurentiis tweeted a photo of himself smiling surrounded by 15 ‘ultra’ leaders, with a message in Italian that translated as “We are Napoli. President and fans united to win!”.
Closing in on their first Serie A title in more than three decades, runaway leaders Napoli had their lead trimmed to 14 points ahead of second-place Lazio, who won 3-0 at Spezia on Friday.
Argentina legend Diego Maradona led Napoli to their only two Italian league titles, in 1987 and 1990.
“There is so much love, passion and affection for the players - perhaps too much - and we will always thank them,” Spalletti said.
“If we manage to do this thing, we will remain forever on the walls of Naples. We will all become Maradona.”
AAP
