Ross Barkley scored his first goal for Chelsea to help defeat Southampton 3-0 at St. Mary's on Sunday.
Eden Hazard and Alvaro Morata also scored as Maurizio Sarri became the eighth manager to go unbeaten over his first eight Premier League games.
Willian had a shot deflected on to the crossbar and Danny Ings missed an opportunity from close range at the other end before Barkley created the opener for Eden Hazard.
Barkley pressed high to win back the ball and set up Hazard, the division's top scorer, who netted his seventh of the league season after 30 minutes.
Barkley, who signed for Chelsea in January from Everton, bundled in the second from Olivier Giroud's acrobatic cross, and Hazard played in Morata to seal the win in stoppage time.
Barkley's goal and assist completed a memorable few days for the midfielder, who has just been recalled to the England squad for Nations League games against Croatia and Spain.
The 24-year-old impressed at the heart of Chelsea's midfield, linking well with Jorginho and Hazard as they completed their ninth win in 11 games across all competitions this season.
"Ross Barkley is playing well," Hazard said. "He scored and made an assist. He is doing well and working hard on the training ground."
Although Southampton should have taken a first-half lead through Ings, who blasted over from just a few yards out, they struggled to match Chelsea's pace and precision.
Ings was lucky to stay on the pitch after a wild second-half challenge on Mateo Kovacic as Southampton, who had six players booked, resorted to increasingly physical methods.
"It's too early to be thinking about the title." Hazard said. "We know it is tough to win, but it is good to be up there.
"We are enjoying playing well and scoring goals. The first half was not so easy. They missed big chances and then we have had a bit of luck for our first goal, but we controlled the match in the second half."