Andre-Pierre Gignac and Andre Ayew both starred, scoring two goals apiece as Marseille crushed Reims 5-0 in Ligue 1 on Tuesday.
Giannelli Imbula was also on target for the visitors, who made it five consecutive victories to stay top in France's top flight.
"It's a fair result, we played very seriously and against a brave rival," Bielsa said post-game.
"It was a very nice match. We had a superiority. We attacked well and defended well.
"Big victories can generate overconfidence, but we'll try to keep grounded. It is of course too early to talk about the title, we just need to continue on this path.
"Draw no conclusion on a portion of the championship, we will judge in the end."
Gignac has played a key role in Marseille's near-flawless start to the season.
The French striker is Ligue 1's leading goalscorer, having taken his tally to eight after Tuesday's brace.
Gignac said he has already turned his attention to Sunday's clash with third-placed Saint-Etienne.
"This victory bodes well for the future," he said.
"We'll have to show Sunday against Saint-Etienne. I put eight goals in seven games so it's good. But thanks to the team."
