PAUL McSTAY last night accused the Celtic players of being unfit and tired during Sunday's humiliating Old Firm defeat.

The Parkhead legend could not believe how many of Ronny Deila's team ran out of steam during the second-half of the William Hill Scottish Cup semi-final.

McStay was at the match and came away deeply disappointed by the result and overall performance, which he felt lacked energy.

READ MORE: Paul McStay is no fan of Deila doctrine after watching attacking traditions tossed aside

Asked about the Celtic manager’s apparent preference for his players to play a pressing game, McStay said: “It wasn't there at all on Sunday. That's why Rangers took control of the game - because Celtic weren't pressing. That high intensity wasn't there.

“The fitness side surprised me. I was thinking, 'why aren't they pressing? Are these part of the tactics, are they sitting off?' But as the game went on I thought a few of the players looked tired. They looked as if they were dying on their feet and that was after 70 minutes.

"To do that high-pressure game you've got to be fit so that comes down to what players do on the training pitch. On my experience, you train the way you want to play. If you train and play at a high intensity in small games, I'd imagine you take that into the game.”

READ MORE: Paul McStay is no fan of Deila doctrine after watching attacking traditions tossed aside

Deila will lose his job at the end of the season and Peter Lawwell, the chief executive, has come under even more criticism than the manager from the supporters over the way he has ran the club during the four-year absence of Rangers.

But McStay insisted the players themselves must take responsibility for Sunday and the other disappointments from a season which will still in all probability end with Celtic’s fifth league title in a row.

He said: "When you come off the park you have to look at yourself in the mirror and ask if you've given everything.

“If you have that's a good starting point. Then you look at the technical side - did you do what you're supposed to do in your position, did you actually play the game you're supposed to?

READ MORE: Paul McStay is no fan of Deila doctrine after watching attacking traditions tossed aside

“Did you implement the instructions the coach gave you as a team before the game? Then physically, were you in the proper physical state to play that game?

"And there's the psychology bit as well. Looking at all of those, you ask 'did we do it right?' And for me there weren't enough ticks against those things on Sunday.

“There was a lot of discussion about the manager’s future before the game. It’s the nature of where we are at the moment, with social media, the stories in the media.

“But from a Celtic fans point of view I just want the players to step up in the next match and get the points needed to secure the title.

“Come the end of the season we can see what needs to be done to move forward as a club - and that will be done."

READ MORE: Paul McStay is no fan of Deila doctrine after watching attacking traditions tossed aside