In Lens, the home took the lead inside 20 minutes via Jhoanner Chavez's left-footed strike and sealed the points just before half-time when Julien Le Cardinal turned into his own net.
It was Lens' second win in two league matches under 31-year-old Still, who took over this summer after making his name at Reims.
Brest have struggled so far, losing both games ahead of their first season with Champions League football, following last term's third-place finish.
After winning their first match, Rennes surprisingly went down 3-1 at Strasbourg.
Andrey Santos volleyed the hosts into the lead in the 23rd minute before Emanuel Emegha doubled the lead shortly after the break.
Ludovic Blas pulled a goal back for Julien Stephan's side three minutes before the hour, but Christopher Wooh's late own-goal handed Strasbourg their first win of the season.
Nantes also picked up their first victory this campaign with a 2-0 win against Auxerre thanks to Moses Simon's 14th-minute strike and 17-year-old Bahereba Guirassy's fine solo effort six minutes into injury time.
Early pace-setters last season, Nice have made a slower start to this campaign, but picked up their first point following their 1-1 home draw with Toulouse.
New signing Jonathan Clauss gave the hosts the lead eight minutes into the second half, before Toulouse's Shavy Babicka levelled matters in the 73rd minute.
Sunday's action ends with Roberto De Zerbi's home league debut at the Stade Velodrome when Marseille host Reims.
