By ESPNSTAR.com staff
Claudio Marchisio netted in the 85th minute to hand his side all three points, after Andrea Pirlo's early freekick was cancelled out by an Emanuele Calaio strike just before the break.
While the victory was enough to see Juve continue their fine start to the season, having picked up six wins and a draw in their opening seven games, Carrera believes there is still plenty of room for improvement.
"Surely this game could have been won much earlier," he said. "We lacked a little ruthlessness, and for this we had to suffer until the end.
"It is obvious that in some matches we may lack a clinical edge, but you cannot always win by four or five goals."
Carrera, who is in charge of the side while Antonio Conte continues to serve a suspension for his role in a match-fixing scandal, also believes defender Giorgio Chiellini was unfairly sent off after picking up his second booking for a lunge on Felipe.
"The first did not seem like a foul worthy of a yellow card," he added. "The second, he was looking to win the ball and even that wasn't so bad."
The Bianconeri are currently top of the Serie A, edging second-placed Napoli on goal difference and four points clear of Lazio and Inter Milan.