It got worse for Frankfurt midway through the second half as Randal Kolo Muani was sent off for a bad challenge.

Giovanni di Lorenzo then added a second, placing into the far corner.

The victory gives Napoli a big advantage for the return leg in Italy on Wednesday, 15 March.

Luciano Spalletti's side have been in superb form this season and sit 15 points clear at the top of Serie A.

They went into this game on the back of five successive wins and looked confident from the outset, with their pace on the attack often causing problems.

Osimhen, in particular, was a menace throughout and he won the first-half penalty when he was fouled inside the box as he tried to retrieve the ball.

Trapp did superbly to deny Kvaratskhelia but could do little to prevent Osimhen tapping in from close range soon after.

Frankfurt's hopes of getting back level were dealt a big blow midway through the second half when key forward Kolo Muani was dismissed for standing on Andre-Frank Zambo Anguissa's foot as they challenged for possession.

Napoli then made the most of the man advantage as they grabbed a second that puts them firmly on course for the quarter-finals as Di Lorenzo finished superbly from Kvaratskhelia's backheel.