By Terry Daley
ROME, Sept 17 (Reuters) - Two of Europe's in-form teams clash in the Champions League on Wednesday when Serie A leaders Napoli take on a Borussia Dortmund side still on a high after hitting six goals in the Bundesliga at the weekend.
Last season's Champions League runners-up Dortmund travel to the hostile San Paolo stadium buoyed by a 100 percent start to their domestic campaign featuring five league wins out of five.
Coach Juergen Klopp could not have hoped for a better dress rehearsal for the Group F fixture in Naples than Saturday's 6-2 demolition of Hamburg SV.
"That was amazing," he told reporters. "It was spectacular how the boys played up front and it was pure fun watching them."
Rafa Benitez's Napoli are top of Serie A for the first time since the great Diego Maradona led them to the title 23 years ago, having scored nine times in their opening three games.
Four goals have come from top scorer Marek Hamsik in a start that has made the fans forget Edinson Cavani's close-season move to Paris St Germain.
"I want to score 20 goals (this season) ... I feel great playing in this system. In only two months you can see the results of the work Benitez has done," the Slovak forward told La Gazzetta Dello Sport.
Hamsik is benefiting from playing in a more advanced role while fellow new signings Jose Callejon and Gonzalo Higuain are also flourishing.
Spaniard Callejon and Hamsik started on the bench for Saturday's home game with Atalanta, rested ahead of the game against Dortmund.
Napoli, though, struggled against dogged opposition and the pair had to come off the bench to guide their side to a 2-0 win, Callejon scoring his third goal in three games.
Benitez's team are looking to improve this season on their run to the second round in 2012 when they threw away a 3-1 first-leg lead to lose to eventual winners Chelsea.
"It's been a radical change with Benitez. We keep possession of the ball more and we're more aggressive, we don't wait for the opposition any more, instead we attack them," said the 25-year-old Hamsik.
New signings Henrikh Mikhitaryan and Pierre-Emerick Aubameyang have also integrated seamlessly into Dortmund's squad and both underlined their early season goal-scoring form against Hamburg.
"We are ready for Napoli," said Klopp. "It is a completely different competition from the Bundesliga and they will be a very tough nut to crack."
Klopp will be without captain Sebastian Kehl who picked up an ankle ligament injury in training on Sunday and is out for six weeks. (Editing by Tony Jimenez)