This is according to former referee Keith Hackett, who exclusively told Football Insider that Jack Iredale’s challenge inside the box on Liam Scales should have been punished.

The Hibernian defender had hold of the Celtic player’s shirt in the 75th minute, which resulted in Scales going down inside the box.

However, the referee did not award a penalty for the incident, and VAR did not advise him to review the challenge, as the Hoops went on to lose late on 2-1.

Keith Hackett: Celtic should have been awarded a penalty against Hibernian

Celtic’s defeat against Hibs was already riddled with controversy.

Auston Trusty was controversially sent off for the Hoops late on, with the club now appealing the decision.

However, the failure to award a penalty could prove to be the most costly.

If scored, Celtic could have easily gone on to win the game, or at least pick up a point, and instead, they came away with nothing.

Even if the Hoops win their game in hand, they would be three points behind Hearts at the summit, as the cost of the Hibs defeat is laid bare.

When examining the footage of the penalty incident, Hackett exclusively told Football Insider: “You have to ask why the officials have taken no action on this clear offence.

“It really is a push from a player on an opponent and should have resulted in a Penalty kick.”

Martin O’Neill insists Celtic are still in the title race

The defeat to Hibs was certainly a massive blow.

Not only are Celtic now six points behind Hearts, but it puts further emphasis on Sunday’s Old Firm derby.

A defeat to Rangers could all but end their hopes of winning the Scottish Premiership title, especially if Hearts beat Aberdeen on Saturday.

As a result, it is crucial that the Hoops bounce back as quickly as possible and put their recent poor results behind them.

Speaking after the match to BBC Sport on 22 February, Martin O’Neill insisted that Celtic remain in the title race despite the latest setback.

He stated: “It’s a setback, that’s all it is. We’re still in the race. There’s not much room for error but we can still fight back.

“I thought we were absolutely terrific. The players put heart and soul into the game. No complaints on that side whatsoever.”

Next up, Celtic face Stuttgart on Thursday in the second leg of their Europa League knockout playoff tie as they look to overturn the 4-1 deficit.