Napoli's defeat at Shakhtar exposed Sarri's centre-forward conundrum

Maurizio Sarri had the look of a man who needed a cigarette. OK, so perhaps that is always true of the Napoli manager - so fond of his smokes that his hometown fan club baked one into a cake for him. Watching him chew his fingers and hang a pen out the corner of his mouth in the away dugout at the Metalist Stadium on Wednesday, though, you sensed that the urge was getting to him on this occasion more than most.

At his press conference one day earlier, he had spoken about the need to start quickly in the Champions League. "In a six-game group, it is clear that the first game will condition everything that comes after," Sarri said. "So it's a hugely important game - more than important, in fact."

And yet, his players had begun sluggishly away to Shakhtar Donetsk, falling behind to a Taison strike after a quarter of an hour. The closest Napoli came to scoring inside the first 40 minutes was on a sliced clearance by Shakhtar defender Ivan Ordets. The Italian side did generate a brief flurry of chances just before the interval, but then gave up another cheap goal to Facundo Ferreyra.

Was Sarri himself to blame? With hindsight, his decision to omit Dries Mertens from Napoli’s starting XI looks like the wrong one. The man who scored 34 goals for this team last season was finally introduced off the bench closely following that second goal, and Napoli was far more threatening thereafter.

The Belgian won the penalty from which the Italians clawed back their lone consolation goal, and Shakhtar's defenders were plainly unsettled by his dynamism. And yet, the man who started in his stead is no slouch. Arkadiusz Milik is the second-most expensive signing in club history: the man Napoli was supposed to be built around, before he found himself on the wrong side of soccer's sliding doors.

Twelve months ago to the day, it was Milik who fired Napoli to victory away to another club from Ukraine, Dynamo Kyiv, scoring both goals in a 2-1 win. The response back home was delirious. The headline writers at Gazzetta dello Sport, Italy's biggest sports paper, dubbed him "dynamite," and "the man who turns crosses into gold."

Milik had already struck twice in a league win over Milan, and followed up the Kyiv game by sticking two past Bologna in his next outing. Just 22 years old at the time, and newly arrived in Naples, the Polish striker had been tasked with replacing Serie A's single-season record goal-scorer, Gonzalo Higuain. He hardly looked fazed by the challenge.

But then he blew out his knee whilst away on international duty. And fate took his job away. Mertens, then a 29-year-old who had spent his entire career on the wing, moved inside and began a goal-scoring tear that not even he could have predicted. During one preposterous December stretch, he found the net nine times in 17 days.

So when Milik came back, Sarri stalled - using the player's lack of match fitness as an excuse to keep him on the bench. After a full preseason, though, that will no longer fly. Mertens remains Napoli’s first-choice centre-forward, but a player of Milik's calibre cannot just sit idly by.

On paper, these are nice problems to have. Between the Champions League, Serie A, and the Coppa Italia, Napoli will need to be able to rotate and give starters a rest at times. The problem is that Milik and Mertens are such fundamentally different players that the team must play differently depending on which one of them is leading the line.

With Mertens, Napoli's attack took on a very distinct playing style - an approach built on rapid movements and interchanges. Flanked by two similarly undersized but technically gifted forwards in Lorenzo Insigne and Jose Callejon, he could assault the spaces behind the defence himself, or just as readily drop deep, pulling defenders out of position and leaving room for his colleagues to do the same.

Milik, by contrast, is a classic No. 9, a focal point who can hold the ball up with his back to goal or get on the end of a cross. Those skills remain as relevant in the modern game as they ever were, but they are very distinct from what Mertens can offer.

It was not that Milik lacked the quality to beat Shakhtar goalkeeper Andriy Pyatov on Wednesday - indeed, he converted the consolation penalty - but that he did not fit together with the team he was playing in. Napoli completed the greatest number of passes of any side in Europe's top five leagues last season. Milik, on Wednesday, made a grand total of 13.

Sarri cannot simply slot him into Mertens' role and expect the team to retain its fluency. Perhaps it would serve Napoli better to have a distinct alternative formation when Milik plays, something that works to his strengths. Or maybe a more subtle tweak can be affected without changing the team's shape.

In either case, though, the manager has little time to start finding answers. Group F of this season's Champions League already looked daunting enough, with Manchester City and the Dutch champions, Feyenoord, completing the slate. One defeat does not condemn Napoli to elimination. But, just as Sarri predicted, it has changed the outlook for what comes next.