Juventus midfielder Arturo Vidal smashed home a second-half penalty to earn a 1-0 win at home to Monaco in an absorbing Champions League quarter-final first leg on Tuesday, leaving the tie on a knife-edge.
Vidal, who has missed two penalties this season, held his nerve and fired into the roof of the net in the 57th minute after Ricardo Carvalho bundled over Alvaro Morata, who had been sent clear by Andrea Pirlo's lofted through ball.
There was controversy surrounding the decision as television replays suggested that the initial contact by the Portuguese defender may have been just outside the penalty box.
"Seeing the incident, it's outside the area," Monaco defender Andrea Raggi told Sky Sport Italia. "You could argue that it continues inside and it is without doubt a foul. The referee had only a few seconds to decide."
Monaco coach Leonardo Jardim also criticised the penalty. "The result was created by an incorrect decision by the team (of officials) that referees," he told a news conference. "This result is not a fair reflection of what happened on the field."
Juventus coach Massimiliano Allegri, whose side faced a Monaco team that had conceded only four goals in eight previous games in the competition, had predicted that the match could be boring but it was completely the opposite.
Although Italian champions Juve dominated possession, Monaco were always a threat on the break and forced Gianluigi Buffon into three top-class saves to deny them an away goal ahead of the second leg on April 22.
Carlos Tevez and Vidal missed excellent openings for a jittery Juventus in the first half and the hosts were lucky to reach the break without conceding a goal.
Yannick Ferreira-Carrasco should have given Monaco the lead when he shot weakly at Buffon and the Belgian had another effort turned away by the veteran keeper shortly afterwards.
Juve playmaker Andrea Pirlo was thrown into the fray for his first match after a seven-week injury layoff and the risk paid off as he set up the winning goal by lofting a pinpoint ball over the defence for Morata.
Carvalho clipped the striker right on the edge of the area and Czech referee Pavel Kralovec hesitated slightly, possibly consulting the goal line assistant, before pointing to the spot and booking the Portuguese defender before Vidal fired home.
Juventus still had another escape to come when Buffon tipped over a rasping Geoffrey Kondogbia drive after the hosts lost possession in midfield and will be more than happy to travel to the French principality with a clean sheet from the first leg.
"It was a good result," said Allegri. "Not conceding a goal at home gives us a small advantage. Monaco are a very-well organised team."