Mane’s 10th-minute strike and a Firmino header on the stroke of half-time put the Premier League leaders in control at the King Power Stadium.
Rachid Ghezzal reduced the arrears midway through a second period the Foxes enjoyed the better of, but Jürgen Klopp’s team remained resolute to secure another victory.
Here are five talking points from the King Power Stadium…
Premier League-era history
Before Saturday, when was the last time Liverpool won their first four league matches of a season?
Top marks if you said 1990-91.
Mane and Firmino’s first-half strikes earned a piece of Premier League-era history for the Reds, who stood firm in the face of strong Leicester pressure in the second half to make it 12 points out of 12 ahead of the international break.