(Reuters) -Fiorentina's Giacomo Bonaventura and Nicolas Gonzalez scored second-half goals to secure a 3-1 win at champions Napoli in Serie A on Sunday after a Victor Osimhen penalty had got the hosts back in the contest.

Fiorentina, who opened the scoring through Josip Brekalo aftr seven minutes, leapfrogged Napoli into fourth spot, level on 17 points with third-placed Juventus, two points behind Inter Milan and four adrift of leaders AC Milan.

Napoli, who on Tuesday squandered an early lead to lose 3-2 at home against Real Madrid in the Champions League, are fifth on 14 points, suffered their second league defeat of the season.

"I am responsible for this defeat tonight as well. However, I did not expect it," Napoli coach Rudi Garcia told DAZN. "We missed a great chance ... and dropped out of the top four."

"There is bitterness, frustration, it's a bad result. We shouldn't have conceded the first goal, the penalty before the interval should have given us an extra push."

Winger Brekalo gave Fiorentina the lead off a rebound from a tight angle in the seventh minute before Napoli striker Osimhen thought he had equalised 15 minutes later but his effort was ruled out for an offside in the build-up.

The Nigerian eventually levelled for Napoli with a penalty in first-half stoppage time after he was brought down by goalkeeper Pietro Terracciano.

Following two close efforts from Fiorentina forward Jonathan Ikone early in the second half, Osimhen could have put the hosts in front just before the hour mark but was denied in a one-on-one with Terracciano.

Fiorentina midfielder Bonaventura then restored the lead for the visitors in the 63rd minute with a precise low strike from near the penalty spot and Gonzalez made it 3-1 in added time from close range.

"Beautiful victory which came in a game prepared in one and a half training sessions, with a great study of the opponent," said Fiorentina coach Vincenzo Italiano.

"That equalising goal could have killed anyone, instead we were good at staying calm."

Fiorentina had won only one of their previous six league games against Napoli, who next travel to lowly Verona after the international break when Fiore host struggling Empoli.

(Reporting by Anita Kobylinska in Gdansk, editing by Ed Osmond and Ken Ferris)