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Frankfurt (Germany) (AFP) - Napoli coach Luciano Spalletti warned his side's "biggest enemy is to think it's done" after Tuesday's 2-0 last 16, first leg win at a ten-man Eintracht Frankfurt.
Napoli won their first ever Champions League away knockout match thanks to goals either side of the half from Victor Osimhen and Giovanni Di Lorenzo.
"It was an end-to-end game, which we want and thrive in.We need to stay calm, very calm," Spalletti told Sky Sports before March 15's return fixture.
"There's the second leg still.Our biggest enemy is to think it's done," he added.
Napoli are 15 points clear atop the Serie A table and look set for their first title in more than 30 years.
Mexico forward Hirving Lozano, who was named player of the match by UEFA, told Sky Sport: "We need to keep working hard to carry on like this.We have to think game by game."
"We did very well against a strong side.It was tough at first but we had a great game."
Frankfurt, who are playing their in debut Champions League season, were reduced to ten men after 58 minutes when France striker Randal Kolo Muani stepped on the shin of Napoli midfielder Frank Anguissa.
Frankfurt midfielder Mario Goetze said the side were left with an uphill battle after Kolo Muani got his marching orders.
"With the red card, I didn't see it but naturally it was a killer at 1-0 down to go a man down."
Goetze, who picked up a yellow for complaining to the referee, said he felt the decision was "harsh" against his star striker.
The 2014 World Cup winner said his side needed to be calmer and criticised himself for the error which led to Napoli's opening goal.
"That cannot happen against a team like Napoli, who can play so well on the counter."
Eintracht manager Oliver Glasner said the difference was how Napoli were able to exploit his side's mistakes.
"We made a mistake on the halfway line and Napoli had the speed and the quality to use it.
"Then we showed our inexperience and our nervousness - and after the red card, the 2-0 result is to be expected."
Glasner, who took Frankfurt to a surprise Europa League triumph last season in his first year in charge, praised Napoli's stunning run of form.
"If you've only lost two games in the past eight months, you get a lot of self confidence and you know what you're doing."