La Rochelle scratched out a 16-11 home victory over Stade Francais on Saturday to move to the head of the Top 14 table.
La Rochelle took the lead with a try after just five minutes.
From a lineout, scrum-half Thomas Berjon burst through the Stade defence and raced 40 metres to score his first La Rochelle try.
Jules Plisson converted and added a penalty after 17 minutes, but the home team were unable to build on their strong start.
"We could have made it easier for ourselves," said home captain Romain Sazy. "It was a pretty bitty match."
Stade winger Telusa Veainu scored his team's try from an interception in the 44th minute, but it went unconverted and La Rochelle kept the visitors at arm's length for most of a lacklustre second half.
Penalties by Plisson and his replacement Ihaia West, sandwiched one by Nicolas Sanchez for the Parisians.
The visitors, who had allowed an average of almost 40 points in their last four away matches, at least stopped the bleeding. They also collected a small reward at the end.
A series of scrums on the La Rochelle line after time had expired yielded only a penalty under the posts.
But when Joris Segonds converted, he cut the losing margin to five points and earned Stade a losing bonus point.
La Rochelle drew level on points with second-placed Racing 92, who beat Castres on Friday.
But they are only a point ahead of Toulouse, who visit Lyon later on Saturday.
"We are very satisfied to have taken the four points," Sazy said. "We are still undefeated at home. We're the only ones in the Top 14, and the objective was to remain so."
The bonus point lifted Stade a place to seventh.
Agen slumped to their 16th successive defeat with a 39-19 loss to Montpellier earning them the unwanted record of the worst ever start to a French Top 14 season.
Perpignan had held the previous run of ineptitude when they slumped to 15 losses in a row in the 2018-2019 season.
Agen, who are rock-bottom of the table with just two bonus points to their name, have not won a game in the tournament since beating Brive 30-20 on February 22 last year.
Bayonne too had a day to forget as they were hit by a 10-try blitz at Clermont who romped to a 73-3 triumph.
Camille Lopez converted all 10 tries and added a penalty to mark the second time this season that the 31-year-old fly-half had enjoyed a 100-percent success rate with his boot.
Apisai Naqalevu, Paul Jedrasiak and Peceli Yato scored tries for Clermont in the first half.
A 47th-minute try from Samuel Ezeala, playing for the first time in 15 months due to a knee injury, secured a bonus point.
Morgan Parra, a second try for Yato, Fritz Lee, Jean-Pascal Barraque, Peter Betham and Japanese star Kotaro Matsushima completed the rout.