It marked a first goal in the Premier League for the Sweden striker.
Aldridge wrote in his column for the Liverpool Echo: "All our goals against Crystal Palace were brilliant, but I loved Alexander Isak's goal.
"He did what myself and loads of other centre-forwards have done in the past. Mac Allister's shot is going wide, but Isak's first touch is brilliant and the finish is right in the corner.
"It's a fantastic forward's finish. He made it himself. It might go down as an assist from Mac Allister, but Isak assisted himself. That's what he's good at and what he did at Newcastle and it's what he can do at Liverpool.
"He needs feeding. We need to establish a sustained formation that works with Isak, Wirtz and Dominik Szoboszlai going forward.
"I used to play the same way as Isak when I was playing for Liverpool. I used to link up and give the ball to Barnsey (John Barnes), to Peter (Beardsley), to Ray (Houghton), even to Steve McMahon, Jan (Molby) or Ronnie Whelan. And then I used to get in the box. The service I got was immaculate."
Aldridge added: "The one thing Isak has to do, however, is hold the ball up. He needs to go up against the centre-halves. Instead, he tends to drift into midfield a bit, which he shouldn't do. We've got enough players in there.
"He's not Bobby Firmino. He needs to get on the shoulders of the centre-halves and move them about and then give it to his midfield, then move. At the moment, he's not quite doing that. But his movement is good, so he's got to learn and the team's got to learn how it works for both."