Allan nearly adds a fourth for Napoli after a teasing run through the middle of the park before the ball breaks to Mertens who smashes the ball across goal and out for a throw-in.
90'
Three minutes of added time shown on the fourth officials' board.
89'
Manchester City have now taken a 1-0 lead in the other game in Group F.
88'
No doubt that Napoli deserve to win after their improved performance in the second 45 minutes but Shakhtar will be frustrated by how quickly they have fallen apart tonight.
86'
Mário Rui enters the game and replaces P. Zieliński.
Zielinski is clapped from the field after his goal and he is now replaced by Mário Rui.
85'
F. Ferreyra gets yellow.
Pepe Reina gets yellow.
Manchester City are still being held to a 0-0 draw by Feyenoord in the other game in this group. Napoli's win now sees them move to within three points of Shakhtar.
Ferreyra is given a card after his part in a bit of handbags on the edge of the box.
Despite his protests Reina is also shown a yellow after the altercation.
83'
D. Mertens has scored a goal for Napoli!
Midfielder Marko Rog nearly makes it three after a powerful run from midfield but his effort is deflected for a corner.
GOAL NAPOLI and Mertens makes it 3-0. From the corner Albiol smashes a header towards goal which Pyatov saves but Mertens is at the far post to nod home.
81'
P. Zieliński has scored a goal for Napoli! Assist by D. Mertens.
Mertens is the man who gets the credit after a sensational inside ball to Zielinski.
GOAAALLLLL NAPOLI 2-0 now they lead and that is thanks to Zieliński. He works a one-two with Mertens inside the box before smashing the ball into the top corner.
79'
Dentinho enters the game and replaces Marlos.
Mertens tries his luck from the edge of the area with that free-kick but he curls it just over the bar but that had Pyatov worried.
Marlos makes his way off the field for Dentinho.
78'
Ismaily gets yellow.
Penalty claims from Mertens as he is fouled on the edge of the box by Ismaily. A yellow card is shown as a free-kick is awarded to Sarri's men.
Minute
Description
77'
M. Rog enters the game and replaces M. Hamšík.
V. Chiricheș gets yellow.
Hamsik is given a rest and replaced in midfield by Marko Rog.
Chiriches goes into the book after pulling back Marlos in the middle of midfield.
75'
Napoli respond by breaking forward themselves but Hamsik sees his left-footed effort blocked on the edge of the box. That was a great team move that deserved more from the hosts.
73'
The game is now becoming more stretched and Shakhtar nearly take advantage as Marlos creeps in behind the Napoli defence but he overhits it and the home team clear.
70'
Alan Patrick enters the game and replaces T. Stepanenko.
Stepanenko has had a quiet night and is now replaced by Alan Patrick.
69'
WOW Zielinski misses an open goal from inside the area. Mertens does well to nip in and move in front of Pyatov who comes rushing out of goal but his lay-off is wasted by his team-mate.
68'
Piotr Zielinski has been very quiet tonight but he grabs the attention as he is chopped down in midfield.
65'
Allan enters the game and replaces L. Insigne.
Insigne receives a huge round of applause from the home crowd as he is replaced by Allan.
64'
Napoli are finding so much space down the flanks but their crossing tonight needs some work as another ball from the left sails into the hands of Pyatov.
62'
Shakhtar seem to have woken up after going a goal down with Bernard and Marlos now coming into the game but Ferreyra is still very quiet and may be in danger of being replaced.
59'
Mertens is flagged offside and the home crowd groan in response. Sarri has definitely got an extra gear out of his side since his team-talk at the break.
56'
L. Insigne has scored a goal for Napoli! Assist by M. Hamšík.
Hamšík grabs the assist after a superb pass carved open the Shakhtar midfield.
GOAAALLLLLL Insigne with a sublime effort to make it Napoli 1-0 Shakhtar. The winger picks the ball up on the touchline before dancing around two defenders and curling the ball into the top-right corner.
53'
Shakhtar under some real pressure here as Callejon glides past Ismaily and cuts the ball back for Diawara but the midfielder sees his shot blocked for a corner. Napoli have two goes to try and alter the scoreline in their favour but the visitors clear on both occasions.
50'
Italy international Insigne is inches away from finding Callejon at the far post with a floating cross but Pyatov is on guard and flies out of his goal to jump and catch the ball.
49'
Napoli threaten again down both flanks as Callejon and Insigne go close with crosses and Sarri is pleased with what he sees as he is quick to applaud from the touchline.
46'
Shakhtar get the match back underway.
Strong start from Napoli as Diawara is allowed space to move forward and he lets fly from distance but his shot is blocked by Shakhtar midfielder Taras Stepanenko.
45'
One minute added on...
44'
Just minutes away from half-time now and this game is there for the taking for both teams after a great first half of football.
41'
Fred tries his luck from the resulting corner and stings the palms of Reina before another set-piece is awarded to the visitors but Ivan Ordets heads over the bar.
40'
A lovely counter attack from Shakhtar sees them win the corner as they work the ball from right to left before Napoli block the incoming cross.
38'
Callejon goes close to getting onto a through ball but the perfect surface at the San Paolo helps Pyatov out and the chance comes to nothing.
35'
The tempo has dropped a little in this Group F clash and that will of course suit Shakhtar as they look to avoid defeat in Naples.
32'
HUGE SAVE FROM REINA - Shakhtar burst into the box on the left-hand side and the ball finds Marlos who spins his way into a shooting opportunity but Reina palms away his effort.
31'
Napoli protest to the official that a card should be given after Elseid Hysaj is brought down but the game resumes at 0-0.
29'
Groans from the home fans after midfielder Marek Hamsik makes his way forward for the first time but he leans back at the crucial moment and blasts the ball into the stands at the San Paolo.
28'
A superb save from Pyatov keeps the scoreline at 0-0 as he stretches out to tip away Insigne's curling effort. A corner is given but Shakhtar head the ball away.
27'
Maggio is shown a card despite pleading with the referee after he crunched into Ismaily.
26'
Yet another break in play after Ismaily is brought down by Christian Maggio but the referee waves away any protests to not give the yellow card.
25'
C. Maggio gets yellow.
24'
More good work from the Ukrainian outfit sees them work the ball to Bernard on the left wing but his cross is too strong and Pepe Reina has an easy catch inside his six-yard box.
22'
Shakhtar have done well to overcome the early pressure and they are now keeping the ball and growing in confidence. Striker Facundo Ferreyra is quiet at the moment but Fonseca's men will look to give him a chance to score before half-time.
19'
The home crowd are on their feet as Mertens is played through the middle but Diawara's pass came a fraction too late and the flag goes up for offside.
18'
Once again Napoil break down the left wing with Insigne and Shakhtar right-back Bohdan Butko gives him too much room but his cross is over hit and the visitors clear the danger.
15'
Worrying signs for Napoli as now Vlad Chiriches has gone down just minutes after Albiol received treatment.
14'
Amadou Diawara floats the ball in from that set-piece but he puts too much power on his cross and Pyatov gathers with ease.
12'
Albiol appears OK to continue but Napoli win another free-kick after Callejon is brought down in the middle of the park.
11'
There is a break in play now as Raul Albiol is down on halfway receiving treatment for an injury.
10'
CHANCE Shakhtar - The visitors prove they will be a threat on the counter as they burst forward before captain Taison receives the ball inside the box but he goes with his right-foot from an awkward angle and fires into the side netting.
7'
Napoli build an attack from the back and the ball is eventually worked towards the edge of the Shakhtar box but the move comes to an end as Dries Mertens is flagged offside.
5'
Shakhtar launch their first attack of the game and Marlos is the man who causes some problems with his dribbling before winning a corner. From the set-piece the ball falls to midfielder Taison but he blazes over the bar.
4'
As expected Napoli have made a positive start with the play going down both flanks as they try to involve Insigne and Callejon.
2'
Big chance for the home side in the first two minutes as Lorenzo Insigne curls the ball over the top for Jose Callejon but the winger sees his shot blocked by goalkeeper Andriy Pyatov.
1'
The match is underway as Napoli kick the game off in front of their home fans.
Hello and welcome along to tonight's live text commentary of Napoli vs Shakhtar Donetsk from Group F in the Champions League. The hosts must win this evening to have any chance of qualiying, while the visitors can progress if they avoid defeat.
Napoli come into this game in fine form and they have won three of their last five games in all competitions. They are first in the Serie A after their 2-1 win over Milan but their European ambitions are hanging by a threat. Maurizio Sarri's troops are third ahead of kick-off after picking up just three points so far.
Shakhtar have also won three of their last five matches but they sit 2nd in Group F just behind Manchester City. They will be confident of getting a result tonight, despite losing last time out to Oleksandria.
Shaktar won the last meeting between the two teams 2-1 but Napoli will be without the suspended Kalidou Koulibaly for this clash. Tonight's team news for the game at the Stadio San Paolo coming up...
Napoli Starting XI (4-3-3): Reina, Maggio, Albiol, Chiriches, Hysaj, Diawara, Zielinski, Hamsik, Callejon, Insigne, Mertens.
Napoli SUBS: Allan, Mario Rui, Jorginho, Maksimovic, Sepe, Rog, Ounas.
Napoli boss Sarri makes four changes to the side that beat Milan with Maggio, Chiriches, Diawara and Zielinski coming in for Kouliably, Allan, Mario Rui and Jorginho.
Shakhtar coach Paulo Fonseca has decided to stick with the same starting XI that lost to Oleksandria and he will be hoping they can get the job done in Naples tonight. The two teams are just finishing off their warm-ups with kick-off fast approaching.
HALF-TIME - Napoli 0-0 Shakhtar Donetsk.
The referee calls time on the first half and both teams will be pleased with their work so far. Napoli have had plenty of joy down the flanks and could have scored on occasions, while Shakhtar have sat back and looked impressive on the counter attack.
Napoli will want to get Belgium international Mertens involved more in the second half as they chase the victory that keeps their Champions League hopes alive. On the other hand, Shakhtar will just do all they can to frustrate Sarri's men as they aim to book their place in the next round of the competition.
Not long to go until the game resumes as Napoli emerge from the tunnel.
FULL-TIME - Napoli 3-0 Shakhtar Donetsk.
Napoli still have a slight chance of qualifying for the knockout stages after a superb win this evening. They have now cut the gap between themselves and Shakhtar to three points but they need results to go their way next time out.
Shakhtar will be left disappointed after a solid first-half display but they were outclassed in the second-half and will be looking for a response in the coming weeks.
That is all for tonight's action, thanks for joining us. Goodbye!
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