Giorgio Chiellini's last minute header gave Juventus an extraordinary 3-2 win at Cagliari in their second game back in Serie A on Sunday.
Juve's Jonathan Zebina and Cagliari's Cristiano Del Grosso were sent off in a fiery encounter in Sardinia where the home side equalised twice with debatable penalties before defender Chiellini nodded in Mauro Camoranesi's free kick.
Italy midfielder Alberto Aquilani, French winger Ludovic Giuly and striker Francesco Totti scored in AS Roma's 3-0 win over Siena while promoted Napoli triumphed 5-0 at Udinese.
Goals were again plentiful on a generally enthralling day of action in Italy with Palermo winning 4-2 at Livorno, who were battered 5-1 by Juve last weekend.
Juve failed to carry that form into the first half at Cagliari with the home side arguably threatening more without really testing keeper Gianluigi Buffon.
However, the second half was packed with incident after David Trezeguet gave Juventus a fortunate lead when the ball ricocheted off team mate Camoranesi and ran into his path, enabling him to score.
Cagliari were almost immediately awarded a penalty when substitute defender Nicola Legrottaglie was adjudged to have held back Alessandro Matri.
Buffon got a hand to Pasquale Foggia's spot kick but the ball spun back and rolled over the line.
FURIOUS PROTESTS
The referee then gave the Sardinians another spot kick but after furious Juve protests the linesman indicated that Chiellini's tackle had been clean and the penalty was annulled.
Buffon then pulled off a remarkable save from Paolo Bianco before Alessandro Del Piero put Juve ahead again when he tapped in a Camoranesi cross which may have gone in anyway.
Cagliari's Foggia equalised with another penalty 10 minutes from time when Zebina was penalised for a foul and the French defender was so incensed he talked himself into a red card.
Del Grosso made it 10 against 10 when he was dismissed for a second booking and Juve finally settled a thrilling game to top the table alongside Roma with two wins from two.
Juve's joy was slightly tempered by television footage showing Zebina threatening a steward after being sent off.
"I hadn't seen that. It is a very ugly scene," Juve coach Claudio Ranieri told reporters, although his winning goalscorer was more supportive of Zebina.
"It is difficult to maintain control when three penalties are given against you. I understand Jonathan," Chiellini said.
Juventus were promoted back to the top flight in May having been demoted to Serie B last year after being found guilty of seeking favourable referees in order to try to fix matches.
Champions Inter Milan beat Empoli 2-0 away on Saturday thanks to a double from Zlatan Ibrahimovic.
Lazio visit Sampdoria later on Sunday and AC Milan host Fiorentina on Monday.
