After heartening victories over Liverpool and English Premier League champions Manchester City during their International Champions Cup campaign, the freshly appointed BVB boss saw his team suffer only their first defeat in nine pre-season outings when they were beaten 3-1 by Napoli on Tuesday.
Watch: Christian Pulisic scores twice as Dortmund down Liverpool
But while results have — overall — been promising, Favre is still hoping to see some significant improvement after watching his team concede six goals in their last two outings.
'Not top, top, top'
"We have a lot to do. It's still not top, top, top," said Favre, whose team had triumphed 4-3 over one of his former clubs, FC Zürich, in a behind-closed-doors friendly also played on Tuesday. "When we lose the ball, we have a problem."
Renowned for their attacking potential with the likes of Marco Reus, Christian Pulisic, Mario Götze and Shinji Kagawa in their ranks, Dortmund are again likely to be one of the Bundesliga's most attractive and exciting sides to watch in 2018/19.
'Lose shape too quickly'
Favre, however, emphasised the need to strike the right balance between defence and attack if the five-time Bundesliga champions are to mount a sustained domestic and European challenge next term.
"Sometimes we have to play more simply instead of taking risks," the former Hertha Berlin and Borussia Mönchengladbach coach explained following the end of the squad's pre-season camp in the Swiss town of Bad Ragaz. "We lose our shape too quickly."