GRAEME Murty last night revealed Rangers' win over St. Johnstone had been marred by an injury to Jamie Murphy that could potentially rule the winger out of the Celtic game next month.

Murphy limped off late on in the Ladbrokes Premiership match at McDiarmid Park following a hefty challenge by St Johnstone midfielder Matty Willock.

It was the last thing that Murty, who confirmed that left back Declan John had suffered a groin injury in training at Auchenhowie on Monday, wanted to see ahead of the Glasgow derby at Ibrox on Sunday week.

Read more: St Johnstone 1 Rangers 4: Graeme Murty's men make it five wins in a row - and cut Celtic's lead to six points​

“There are a few knocks, a few sore ones," he said. "Jamie was the most obvious one. There are a few people with bruised and battered bodies because we have gone through quite a testing schedule.

"But we will just assess those, particularly Jamie, and try to get them rested down as soon as possible because we have got big games coming up. He was in a bit of pain and he was a bit frustrated and a bit angry with some of the tackles that he had.

"But when you are an influential player and you hold onto the ball as he does people are going to want to be robust and stop you playing. It is part of the game.

"We have to assess his foot and then we will go from there. I don’t want to jinx anything by saying how bad it might be, I don’t want to talk ourselves into it. We will assess it, we will try and be calm about it and we will make sure that he will get the requisite care.”

Murty confirmed left back John had been left out of the Rangers team as a precaution ahead of the William Hill Scottish Cup quarter-final against Falkirk on Sunday and the Premiership game with Celtic the following week.

He said: “Declan felt discomfort in his groin on Monday so it’s too soon to give any detailed information. There was no point in risking him with so many big games coming up.

“We’ll get him assessed and make sure with the rest of the group that he’s ready and in a fit state to go."

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Alfredo Morelos, who has been the subject of several failed bids from Beijing Renhe in recent weeks, netted the fourth goal to take his tally for the season to 17.

The Chinese transfer window closes this evening and Renhe could theoretically make another offer for the Columbian striker today.

However, Murty revealed he was confident of keeping the Columbian striker until the end of the 2017/18 season at least.

“I’m still relaxed about the Alfredo situation," he said. "I can’t do anything about what they do. If they come in with a ridiculous bid that the club want to talk about then we’ll have a conversation.

“But until that happens I’ve got a centre forward who is adding to our collective and scoring goals and looking like he’s really got his mind focused."

Meanwhile, Murty, whose side reduced the lead that Celtic, who have played a game less than Rangers, have at the top of the Premiership to six points with their fifth consecutive triumph, revealed his players had been subdued after the 4-1 win.

"The interesting thing for me is that we have got quite a flat changing room because they felt that the last 30 minutes weren’t of the required standard, weren’t of the standards that they’ve set," he said.

"I’ve had to work quite hard at getting them up and not being down on themselves. That is indicative of the culture that we’re trying to set and the standards that they’ve set for one another. They said the last half hour wasn’t good enough and they need to be better and that’s great for me to hear."

Tommy Wright, the St Johnstone manager, was disappointed with how easily Rangers had been able to score against his side and admitted the Perth club had allowed themselves to be bullied by their Glasgow rivals.

“We are back to the way we have been at home this season," he said. “The game was dead at half-time after we gave away soft goals. That has been our Achilles heel all season. We were bullied by Rangers and the last two games against them that wasn’t the case.”