BARRY FERGUSON has insisted Rangers have "let a lot of people down" after the dire derby defeat to Celtic.

The Ibrox hero had been expecting a "belter" of a clash between Rangers and Celtic at Parkhead yesterday - but he was left gutted as he branded the 4-0 defeat a "sore one".

And Ferguson expects the Rangers side to come in for criticism over the manner of the defeat with simple mistakes proving costly.

Rangers legend Ferguson had expected Rangers to seriously compete as he suggested Giovanni van Bronckhorst had Ange Postecoglou "sussed" before the match.

Unfortunately for Ferguson, Celtic were well on top all afternoon as they raced into a five-point lead at the top of the table.

Reacting to the result on Go Radio's Football Show, Ferguson said: "I suspect that he'll [Gio van Bronckhorst] will not be a happy man. And neither he should be.

"The goals, it's not good enough at that level. It can happen once in a game, but you can't let it happen a second and third time. Plain and simple. Celtic were the better team.

"And they [Rangers] are going to come in for a bit of flack, no doubt about it.

"They've let a lot of people down and if they are professionals they'll know they've let themselves down.

"But there is no getting away from the fact that Celtic were stronger in all departments and it's a sore one. A sore, sore one to lose."

In his Daily Record column ahead of the match, Ferguson had claimed Van Bronckhorst knew how to get a result but warned over their eventual downfall; failing to match Celtic's relentless pressure and remaining switched on.

He wrote: "For me, the key will be the first 10 to 15 minutes because what happens in those early exchanges could very well set the tone for the entire match. But no one will know that better than Gio and there were signs towards the end of last season that he might have got Ange Postecoglou sussed. Put it this way, the 1-1 draw at their place at the end of the season should have been a Rangers win and that tells me that the manager knows exactly how to combat Celtic’s all out attacking style.

"He won’t go there looking to stand toe-to-toe with them. He’ll want his team to be nice and compact and solid from the start. Most importantly of all, he’ll demand his players match the energy of Celtic’s because these guys will be coming at them from all angles.

"If Rangers aren’t prepared to go with them stride for stride, matching their runs, then it could quickly become a very long afternoon. But I really believe Gio has worked that out for himself. He’s a guy who studies every opponent and then comes up with his own plan for that specific opponent."