Daniele De Rossi scored the only goal of the game from the penalty spot as Italy beat Bulgaria on Sunday night in Palermo to take over top spot in Group H.
De Rossi struck in the sixth minute after Veselin Minev fouled Antonio Candreva inside the area. The veteran Italian midfielder later earned himself a red card 10 minutes after the restart for retaliating after a bad tackle by Ilijan Micanski, who was also sent off.
Bulgaria had chances to equalise but neither side found the net the rest of the way in an entertaining Euro 2016 qualifying encounter.
The win has lifted Italy above Croatia and Norway into first place with two games remaining. Defeat means that Bulgaria are now unable to catch Croatia, who are third and hold the last playoff spot.
The Azzurri, who had not lost a competitive home qualifier in 16 years, made five changes to the side that struggled to beat Malta 1-0 at home last Thursday.
Coach Antonio Conte left out veteran playmaker Andrea Pirlo from the starting XI with De Rossi taking his place in midfield.
Stephan El Shaarawy replaced Citadin Eder in attack playing alongside Graziano Pelle, who scored the goal against Malta.
Italy took an early lead after the referee pointed to the spot when Candreva drew contact from Minev inside the area.
De Rossi struck the penalty into the back of the net but he had to retake it due to encroachment.
The Roma midfielder made no mistake for a second time and although Bulgaria goalkeeper Bozhidar Mitrev guessed correctly he could not stop the ball from going in.
Bulgaria almost pulled level in the 18th minute had Italy goalkeeper Gianluigi Buffon, making his 150th appearance for the Azzurri, not made a stunning save.
De Rossi gave the ball away in midfield and Ilian Micanski surged towards the Italy area before drilling a right-footed strike from 20 yards that Buffon kept out.
At the other end, Pelle headed Marco Verratti's cross over the bar.
Italy had a good opportunity just shy of the interval when Candreva got a toucn on Mattia De Sciglio's low cross towards the box but his attempt was saved by Mitrev.
The home side continued to press forward after the break and one minute into the second half, Mitrev did well to clear
Marco Parolo's' powerful shot that had taken a deflection off a defender.
Both teams were down 10 men in the 55th minute, with De Rossi sent off for the first time for Italy since the 2006 World Cup.
Six minutes later and Mitrev came off his line to clear Candreva's dangerous pass towards an unmarked El Shaarawy.
The hosts should have killed the game off in the 88th minute but Leonardo Bonucci's header from substitute Alessandro Florenzi's free-kick went just over the bar.
Georgi Milanov almost made Italy pay when he found space in the area and powered a right-footed shot at Buffon, but the Italian was able to block the attempt as the Azzurri held on for a narrow win to remain unbeaten in qualifying.
Italy travel to Baku to face Azerbaijan on Oct. 10 before ending the qualifying campaign at home to Norway three days later.