The Spanish champions have won all five of their matches in all competitions, scoring 22 goals and conceding only three ahead of Sunday's La Liga trip to Levante.
Flick has been delighted with the way his team have started but knows football can change quickly.
"We know in football things can change very fast. I like that we are enjoying the situation right now," the Barcelona coach said.
"If we change something from this attitude, we'll go in the wrong direction and this is what we don't want."
Barcelona have produced some impressive attacking displays, with Raphinha and Lamine Yamal among the players making a major impact.
They scored five goals against Feyenoord in the Champions League and also put five past Rayo Vallecano, while recording convincing victories over Valencia and Elche in La Liga.
However, Flick insists Barcelona must reproduce the same intensity in every match.
"We're very happy we are playing on this level but we know that we have to show it in every game," he said.
"We know we have huge quality but we also have things we're doing that are important for us. When we keep the intensity high, we are focused and we are active."
Barcelona have set their sights on major honours this season, with the Champions League the biggest prize after last winning the competition in 2015.
Flick said winning the Champions League is the club's dream, while president Joan Laporta has also made retaining the LaLiga title a major objective.
"I spoke with the fans, with the people in Barcelona. This year we have to win the Champions League and of course this is a dream for us, this is our objective to win this," Flick said.
"The president also said that La Liga is also important, and to win La Liga three times in a row, it would be amazing."
Kylian Mbappe has backed himself to win the Ballon d'Or after a remarkable individual season, insisting there was no player better than him despite Real Madrid and France falling short of major honours.
Sevilla snatched a hard-fought 1-0 victory over Valencia at the Estadio Ramon Sanchez Pizjuan to climb into La Liga's top four, while their opponents remain rooted to the bottom of the table.
Barcelona have moved quickly to secure the future of Egyptian teenager Hamza Abdelkarim, with the 18-year-old set to sign a new contract running until 2030.
Joao Cancelo has set his sights on Champions League glory with Barcelona after making his first start of the season on Wednesday in their impressive opening 5-1 win over Feyenoord.
