The Catalan trainer believes his team are still some way from firing on all cylinders, despite winning their opening five Liga games this term, ahead of the clash with Sevilla
The Catalan giants currently lie two points clear at the top of La Liga and eight points ahead of fierce rivals Real Madrid, while they opened their Champions League campaign with a victory over Spartak Moscow.
"There have been games where we have been at a high level and others that our start has cost us in," the 42-year-old told reporters.
"As we go through the season we will be looking to develop a further rhythm. We are currently not playing at 100 per cent.
"But I do think we are physically stronger than we have been in the past, because these are virtually the same players."
The next opponents looking to end Barca's perfect start will be Sevilla at the Ramon Sanchez Pizjuan, and Vilanova is adamant that the fixture will represent a stern challenge for his team, particularly with five defenders currently absent through injury.
"It always affects you when numbers are this low, but for a club like this, with so many games, we are used to it," he added. "Some will recover for Lisbon and others for the Clasico, but we will have to wait.
"When the injuries are concentrated on a certain position in the field then it does further complicate matters, but I saw [Alex] Song do very well the other day at centre-back."
"All games are tough but it is true that the Pizjuan is not an easy ground to go to. I spent the worst 15 minutes of my life there [with Barcelona in 2009-10].
"We were 3-0 up, then it was 3-2 and they could have drawn against us even though they had 10 men. Sevilla are in great shape, they have conceded the fewest goals in the league [alongside Malaga with two] and it will not be easy."
Vilanova also spoke about Lionel Messi's clash with David Villa last week, and was keen to declare the matter closed.
"Villa-Messi? This is a part of football. Nothing happened that was not normal," the Catalan trainer concluded.