PEDRO Caixinha, the Rangers manager, has two fresh injury concerns ahead of the opening Old Firm game of the season following his side's Betfred Cup quarter-final win over Partick Thistle last night.

Bruno Alves, his centre half, and Declan John, the second choice left back who was standing in for Lee Wallace, had to come off in the second half of the last eight match at Firhill last night.

Caixinha admitted that both Alves, who suffered a calf strain and John, who picked up a thigh knock, were a doubt for the Ladbrokes Premiership match against Celtic at Ibrox on Saturday.

Ross McCrorie, the 19-year-old defender who made his first team debut when he came on for Alves, could now be handed a start against Brendan Rodgers's side this weekend.

But Caixinha believes the Scotland Under-21 internationalist is destined to become one of his country's best ever defenders and stressed he will have no hesitation to pitch him in.

"I had to take Bruno and Declan off at the same time," he said. “Both have problems and that is the reason I was forced to make the substitutions.

“We know we have four days so we need to assess them over the next 24 to 48 hours and see whether we have a clearer idea if they can make it. I need to know before I can make my decision for Saturday.

“Ross McCrorie is going to be one of the best centre halves in history, not just for this club but for this country. You just need to see what he did. He was brilliant.

“It’s not about age or names. It’s about getting the chance to prove it. I have no concerns about him. I never had and never will have. If he needs to play on Saturday, he will play. If Declan is unavailable then we have Lee (Hodson) and an option as well

“I play one game at a time. I know what I want to do on Saturday. The boys will have a day off and then we will prepare. The main concern is to recover."

Caixinha's side surrendered the narrow lead which a Carlos Pena strike had given them in the second half against Thistle in the last minute of regulation time when Kris Doolan netted an equaliser.

But extra-time strikers from Daniel Candeias and substitute Eduardo Herrera ensured they triumphed 3-1 and progressed to the semi-final of the competition.

The Rangers manager believes the victory will have given his players a lift ahead of their first meeting of the 2017/18 campaign with Celtic on Saturday.

He said: "They are different matches, but of course they are connected. If we were eliminated then of course the confidence would have been knocked down. So it’s important to win, especially a knockout match.

“Let’s see what this competition has for us. No matter what happens in the draw we are thinking about getting to Hampden for the final. You could see the confidence after we went two goals up. "