Antonio Conte felt Napoli paid "a price" for the "cumulative effect" of fatigue during their 2-0 defeat by Benfica.

The injury-hit Partenopei were beaten by goals from Richard Rios and Leandro Barreiro at Estadio da Luz, where they were playing their sixth game in the space of 18 days.

Napoli have suffered five successive away defeats for the first time in major European competition, while it is their longest winless run on the road since a streak of nine between October 1994 and November 2011.

Napoli fielded the same starting XI that began their Serie A victory over Juventus on Sunday, and fatigue was evident in the visitors' performance.

Conte was not too surprised at his players' levels, as he praised the efforts of his depleted squad during the busy period.

"The truth is that we weren't sharp from the very start," he told Sky Sport Italia. "In those [previous] games, we used up a lot of physical and mental energy.

"I had talked about energy going into this match because I knew that, in the long run, we'd pay a price. We struggled.

"We wanted to be aggressive, but made a mistake with the press, allowed a dangerous attack, and it scared us. So, we were too stretched out in the first half, weren't aggressive enough in the press.

"Having said all that, it's understandable. We knew the difficulties of this match, and when they start to pile up with six in a row every three days, you will inevitably pay a price. 

"The lads were generous, they tried to the very end to give their all, but you could tell they weren't sharp, weren't making the right decisions and lacking quality. I cannot reproach them, as they gave everything they had.

"It's a cumulative effect of so many games that in the end weigh on you. This is what we've got, and I am proud of these lads for giving their all, but you could tell we were lacking that sharpness."

That defeat left Napoli 23rd in the league-phase table, just a point clear of Benfica in 25th, leaving their hopes of progressing to the knockout play-offs in doubt.

The reigning Scudetto holders' final two matches of the initial phase see them travel to Copenhagen on January 20, before hosting Conte's former side, Chelsea, eight days later.