Ange Postecoglou’s side took control of the title race on Wednesday night when they beat Rangers 3-0 at home to move to the top of the Scottish Premiership table.
Celtic are still just a point ahead of Rangers in the league table, but they have looked like the team to beat since the winter break whereas their Glasgow rivals have dropped points.
Hartson conceded that Postecoglou’s Celtic side are a very different team to what everyone saw last season and at the start of the current campaign.
He lauded the way the Celtic players showed intensity on the pitch to win the ball back and expressed his delight at the way they attack opposing sides in droves in every game.
The former Bhoy said on the Go Radio Football Show: “Celtic lately are a different proposition to what they had been.
“The way that they play, the way they hunt down the opposition when they have got the ball and they win it back quickly.
“And they attack and they are a huge attacking force with really good and talented footballers in that team.”
Celtic will look to keep the momentum going when they will travel to Motherwell on Sunday.
