Dusan Vlahovic struck twice as Fiorentina ended AC Milan's unbeaten Serie A record on Saturday with a thrilling 4-3 win in Florence, while Leonardo Bonucci scored two penalties in a 2-0 win at Lazio.

Vlahovic, who had been under fire from Fiorentina fans for refusing to sign a contract extension, put the hosts into what looked like a safe three-goal lead an hour into an error-strewn contest at the Stadio Artemio Franchi.

And he saved the home side again with five minutes to go by coolly finishing the fourth following Zlatan Ibrahimovic's two quick strikes, giving Fiorentina their first win of the season against one of Italy's big boys.

Vincenzo Italiano's Viola are up to sixth on 21 points, four away from the Champions League positions, after a win in which Alfred Duncan and Riccardo Saponara also netted for the hosts and Lorenzo Venuti -- only playing in defence as three centre-backs were out injured -- scored an unfortunate stoppage-time own goal.

"I told the boys we are getting the reputation of being a team that can't do it against the big clubs and that this was the time to show that it's not the case," said Italiano.

"It was a great achievement and I am very happy for the players."

Milan's first league defeat in their 13th match of the season meant they missed the chance to go top and remained level on 32 points with league leaders Napoli, who take on third-placed Inter Milan at the San Siro on Sunday.

"It was a very unusual match," said Milan coach Stefano Pioli to Sky Sport Italia.

"We played well in the first half and shouldn't have been 2-0 down, but that's football, we didn't score our chances and we were made to pay for our errors."

Milan goalkeeper Ciprian Tatarusanu gifted Fiorentina the lead in the 17th minute, dropping an easy catch from a corner and letting Duncan poke home the opener.

Vlahovic then headed over a good chance before Milan responded with Sandro Tonali and Rafael Leao both having good shots saved and Ibrahimovic somehow heading a gift-wrapped chance wide.

Saponara then punished Milan with a superb curling strike in first-half stoppage time and when Vlahovic danced round Tatarusanu to make it three the match looked done and dusted.

The hosts then immediately proceeded to shoot themselves in the foot, Giacomo Bonaventura rolling the ball to Ibrahimovic in the area and allowing the Swede to fire Milan back in the game in the 62nd minute.

Ibrahimovic then cut the deficit to one with a tap-in from Theo Hernandez's cross, but Vlahovic saved the day with his 10th league goal of the season -- after Nico Gonzalez picked Hernandez's pocket -- which puts him level with leading scorer Ciro Immobile.

Leonardo Bonucci struck twice from the penalty spot in a 2-0 win at Lazio which continued Juventus' climb up the Serie A table following a rocky start to the campaign.

Italy defender Bonucci smashed home almost identical spot-kicks in each half at the Stadio Olimpico in Rome to move Juve seventh, level on points with Fiorentina and fifth-placed Lazio.

It was a dogged, solid away performance typical of Massimiliano Allegri's best sides and a good sign ahead of Tuesday's trip to Stamford Bridge to face Premier League leaders Chelsea.

"When you're Juve and played like we did at the start of the season it's right that you get criticised, but that should encourage us to improve," said Bonucci after his first Serie A double.

"It's down to us to maintain the same spirit from tonight."

The win for Juve was their first by more than one goal in Serie A this season, and they stay some way off pace-setters Napoli and Milan.

Atalanta's 5-2 demolition of Spezia in Saturday's early match keeps them fourth, level on 25 points with Inter.