Liverpool dominated Chelsea at Stamford Bridge in what could have been a difficult opening away game.
The home side were reduced to ten men just before half time when Mane was hauled back by Anders Christensen who denied a clear goalscoring chance.
But Sadio Mane scored twice within four minutes of the second half to secure the points for the reds.
Thiago Alcantara made his Liverpool debut in the second half, replacing Jordan Henderson and there was even time for Alisson Becker to make his first proper penalty save as a Liverpool player when he denied Jorginho.
It maintains Liverpool's successful start to the season.
Alcantara named on bench
There was a surprise in the team news - with both Joe Gomez and Joel Matip ruled out with muscle injuries, in stepped Fabinho to provide cover as centre-back. Jordan Henderson returned to the starting line up alongside Wijnaldum and Keita.
New signing Thiago was named on the substitutes bench.
Chelsea had new boys Timo Werner and Kai Havertz making their home Premier League debut but it was Liverpool who settled much quicker with Chelsea struggling at times to get out of thier half.
Their brief forays usually saw the ball arrive at Timo Werner's feet before Fabinho took it off him. He was excellent at the back and looked at times the more accomplished and senior member next to Virgil van Dijk.
Few chances were fashioned by Liverpool although Wijnaldum had gone close with an effort from the edge of the area.
Just before the interval, Henderson unleashed Mane with a great through ball but Christensen wrapped his arms around his neck and hauled him down. The referee gave a yellow card before reviewing the incident on the pitchside monitor. Yellow card discarded and replaced with a red.
Jordan Henderson was withdrawn at half time after feeling tightness in his thigh, which allowed Thiago Alcantara the opportunity to make his debut. Chelsea too removed Havertz, bringing on defender Tomori to try and keep Liverpool out.
It wouldn't work.
Thiago glided into the Liverpool team effortlessly. His 75 completed passes in the second half was more than any Chelsea player managed in the full game, and was the most by a player who had only played 45 minutes since passing data has been recorded in the Premier League 18 seasons ago.
His only blemish was getting the faintest of touches on Werner which allowed the player to tumble and gain a penalty later on. A penalty that Alisson would save from Jorginho.
However, it was Mane who would grab both of the goals in the game. Salah and Firmino combining in the 50th minute, before Bobby lifted the ball up for Mane to rise and smash in a header.
Four minutes later, Mane reacted quickest to losing the ball, chasing down Kepa Arrizabalaga's clearance before smashing into the net.
If last week was all about Salah's hat-trick, then Mane was back in the mood tonight. Five goals from Salah and Mane in the opening two games showing the internal competition amongst our attackers.
James Milner came on for his 150th appearance and there was a late cameo for Minamino.
Liverpool even walk away with a clean sheet. This week was much more like it!