Summer arrival Marko Grujic scored his second pre-season goal in the first half, while Alberto Moreno struck from the penalty spot in the 90th minute as the Merseyside outfit took home the Shankly trophy as a prize.
Long-time pals Jurgen Klopp and David Wagner were in opposing dugouts, and despite being a friendly, there was a competitive edge to the game as Liverpool looked sharper, played plenty of one-touch football and closed down their opponents when off the ball.
The early chances of the match, though, fell to Huddersfield as Joe Lolley came close to scoring from the edge of the area thanks to some sloppy play from Lucas Leiva, who gave the ball away in his own half minutes beforehand.
Lolley ended up sending the ball wide of the far post, and his teammate Rajiv van La Parra did the same shortly afterwards when he cut into the corner of the box.
The £36m summer signing moved towards the centre of the danger area before unleashing a left-footed shot, but the ball trickled wide of the post.
Mane got to the ball first, but the goal was disallowed for a foul on the keeper, and at the other end, Liverpool's keeper Loris Karius was called into action when Aaron Mooy's square ball found Lolley, who tried to curl a shot into the net, but the German palmed clear.
The breakthrough was made just after the half-hour mark when Roberto Firmino overlapped Mane to get the ball on the left side of the area before crossing it into the feet of Grujic, who took a touch before drilling the ball past Coleman.
Just three minutes later, the visitors were awarded a penalty when Mane was taken out by Coleman in the box, and the shot-stopper would likely have been sent off in a competitive fixture.
Coutinho had the opportunity to double Liverpool's lead in the first half, but it was not to be as his shot towards the bottom left corner was palmed away by the keeper.
After the break, with both sides having made wholesale changes, the tempo dipped and chances were few and far between in the first 15 minutes.
Kyle Dempsey came closest to scoring in the opening exchanges of the second half when the ball was pulled back in the box to his feet, but the midfielder's shot flew over the crossbar.
Trent Alexander-Arnold tried to impress Klopp by whipping the ball at pace into the box, but goalkeeper Luke Coddington managed to punch clear before a red shirt could get on the end of it.
There was an injury concern for Liverpool when Lucas pulled his hamstring while running to intercept a pass, and Klopp was forced to bring on goalkeeper Shamal George to replace him as he had already used all of his outfield options.
Dempsey impressed for Huddersfield in the second half as he created the majority of the team's chances, one of which was produced from a driving run down the middle of the park.
The midfielder thumped a shot towards the bottom left corner, leaving Karius scrambling across his goal, but the ball drifted wide.
Huddersfield had more of the ball in the second half and were able to frustrate their opponents, but it was Liverpool who came out on top as Moreno scored from the spot after Ryan Kent was brought down in the penalty area.
Liverpool will now travel to the United States to face Chelsea and AC Milan in the next leg of their pre-season schedule.