Maurizio Sarri said he cannot rotate Lorenzo Insigne as the "world class player" is too important for Napoli following their Champions League victory.
Insigne scored a stunning goal to lead Napoli to a 3-0 win at home to Shakhtar Donetsk in Group F action on Tuesday.
Deemed surplus to requirements in Italy's failed World Cup qualification bid against Sweden, Insigne struck against AC Milan in Serie A last week and the star forward was at it again as Napoli accounted for Shakhtar.
"This is Lorenzo. He has improved so much over the last three years, become a world class player who I think has to be left out of squad rotation too, because he is so important," Sarri told Mediaset Premium.
"We can give him a rest for the final 20 minutes, but to drop him from the start – I can't do it."
The win boosted Napoli's hopes of progressing to the knockout round in the Champions League.
Napoli are still third in Group F, but they only trail second-placed Shakhtar by three points with one matchday remaining as Manchester City sit six points clear.
"We wanted the three points at all costs," Insigne said. "We know it doesn't only depend on us, but we hope City will beat Shakhtar and we can get our result away to Feyenoord."
On Sarri, Insigne – who was dropped by former Italy head coach Gian Piero Ventura for the World Cup play-off – added: "I thank the coach, as since the first day he has always put his faith in me and I tried to repay him with performances, goals and assists.
"I'll never stop putting myself at the disposal of the coach at any moment of the match."
|Rockets star Paul dealing with hamstring injury|
|Does he only care about his hair? - Denmark coach Hareide slams Pogba, France|
|Rockets push Warriors to brink of elimination|
|World number 84 Kicker suspended for match-fixing|
|WATCH: Paul shimmies in Curry´s face|
|Copa Libertadores Review: Estudiantes into last 16 after thrilling win over Nacional|
|Ronaldo: Cristiano and Neymar would be good together at Madrid|
|Rockets honour Santa Fe victims, first responders at game five|
|Real Madrid rejected €150m offers for Asensio – agent|
|Marshall, Baldwin react strongly to Trump´s comments on NFL anthem stance|
|Nabura handed six-week ban for wild kick|
|Pedroia to return for Red Sox on Friday|
|Warriors´ Iguodala ruled out for game five against Rockets|
|Na leads as Spieth makes solid start at Colonial|
|James Harden, LeBron James headline 2017-18 All-NBA first team|
|Manchester United target Fred to decide future after World Cup|
|´Incredible´ Salah is like Messi, says Ronaldo|
|Salah a big candidate for Ballon d´Or - Muller|
|Message from coach keeping Masters champion Reed grounded|
|Anybody can really win it - Seles feels French Open is wide open this year|
|Mambo number 5! - Non-league star channels Lou Bega hit|
|Pakistan to stop wearing smart watches after ICC intervention - Hasan|
|Saha hails ´great man´ Ferguson as legendary Man Utd boss continues recovery|
|Emery´s depth of knowledge impressed Arsenal´s Gazidis|
|Conceicao extends Porto contract|
|Lomax impresses as Saints overrun Tigers|
|McIlroy in contention at Wentworth as Bjerregaard sets the early pace|
|Bad light calls time on Thiem, Wawrinka out in Geneva|
|Garitano in, Canales out at Real Sociedad|
|Caparros accepts new role at Sevilla|
|Pliskova downed by Larsson after drawing Serena in Paris|
|They´re using the anthem as fake patriotism - Warriors coach Kerr critical of NFL|
|Lyon win record fifth Women´s Champions League title|
|French Open 2018: Doing the unthinkable - the men most likely to topple Nadal|
|French Open 2018: How can Rafael Nadal be stopped?|
|Steve Smith named as marquee player for Global T20 Canada|
|Can Emre play? Yes he Can... and so can Milner|
|Liverpool working to help fans after flight cancellations|
|Abbas and Hasan torment sorry England|
|Xavi ´thrilled´ to sign two-year Al Sadd extension|
|Holtby extends Hamburg contract despite relegation|
|Nadal begins French Open defence against Dolgopolov|
|Serena drawn to play Pliskova in French Open first round|
|FA condemns assault of match official|
|Bologna confirm Donadoni departure|
|Yates lead halved in Giro d´Italia|
|Connacht turn to Friend|
|Scotland lose injured Dunbar for June tour|
|Spalletti in ´no rush´ to sign new Inter deal|
|Ricciardo and Red Bull dominate Monaco practice|
|Mauricio Pochettino signs new deal with Tottenham|
|Pochettino signs new deal with Tottenham|
|Istanbul to host 2020 Champions League final|
|Williams sisters given French Open wildcard|
|President Donald Trump praises NFL´s anthem stance|
|Buffon in consideration for Italy call, says Mancini|
|Roberts injured in Broncos win against Eels|
|Atletico complete move for Villarreal star Rodri|
|Ozil, Gundogan not playing politics, says Low|
|Valencia complete permanent Kondogbia signing|
|Fairytale ending could be in the script, says World Cup-bound Vardy|
|Milwaukee police apologise to Bucks´ Brown over tasering|
|Television, crosswords and Nintendo - Koscielny´s remedy to World Cup heartache|
|World Cup not an audition for Barca or Madrid, says Germany star Werner|
|Neck injury rules Kohli out of Surrey stint|
|Nine LaLiga titles and 674 club games under nine managers - Iniesta in Opta numbers|
|49ers Enterprises takes stake in Leeds United|
|Manchester United should sell Pogba if he´s unhappy - Scholes|
|Andres Iniesta´s nine LaLiga triumphs with Barcelona|
|Andres Iniesta: The footballers´ footballer|