Napoli came into this game staring down the barrel of four successive European defeats for the first time, but they made the ideal start in their attempt to avoid that record when Leonardo Spinazzola made a run down the left wing, and his cross was volleyed into the net by Matteo Politano with just 53 seconds on the clock.
Smart reactions from visiting goalkeeper Nikita Haikin prevented further early Napoli goals, as he got down well to deny Noa Lang and Giovanni Di Lorenzo, while a vital Jostein Gundersen deflection sent Scott McTominay’s effort wide after a driving run into the box.
The Partenopei’s dominance was continuing when Rasmus Hojlund and Lang were both played through, but the Dane could only strike the side netting and the Dutchman was again thwarted by Haikin.
However, that dominance was ended abruptly when Sondre Brunstad Fet worked the ball into the left side of the Napoli area where Jens Petter Hauge was arriving to guide the ball into the bottom corner, equalising with the away side’s first real opportunity.
The Norwegian side came close to taking the lead when Ole Didrik Blomberg beat Alex Meret to a long ball over the top, only for the backtracking goalkeeper to recover to dive on Blomberg’s centre.
A third goal did arrive before half-time, but it was Max Allegri’s side who got it, as Kevin De Bruyne played an inch-perfect pass through to McTominay, whose poked shot deflected beyond Haikin.
Only Lille had fewer attempts than Glimt’s 13 over the first two matchdays, and though they were creating more early in the second half, they weren’t clinical enough as Blomberg failed to direct his header from four yards out before Sondre Auklend failed to prod the ball past Meret, also from close range.
Those misses nearly came back to bite when De Bruyne and McTominay combined again, but this time the Scotsman’s shot came back off the post.
As it turned out, it was Napoli who were left rueing wasted chances, as Fet added a second assist by slotting through to Andreas Helmersen, who worked a pocket of space and fired past Meret.
Meret palmed away a powerful Patrik Berg strike before Haikin positioned himself well to clutch another from Lang as both sides looked for a winner, but 15 minutes from time Gli Azzurri went ahead for the third time when Politano produced an excellent delivery from out wide for the leaping McTominay to power past Haikin with his head.
Kjetil Knutsen’s side pressed for a third equaliser late on, only to cough up possession deep in their own half to Giovane, whose pass across goal was diverted into his own net by Odin Luras Bjortuft.
Sondre Fet powered a late consolation into the top corner, but it’s just a third away defeat in nine in the UCL for Glimt, while Napoli boss Max Allegri ended a five-game losing streak in the competition.
Flashscore Man of the Match: Kevin De Bruyne (Napoli)