Ange  Postecoglou revealed captain Callum McGregor picked up a “significant” facial injury in Celtic’s 2-1 Scottish Cup win against Alloa

With the visitors leading through a Giorgos Giakoumakis strike the Scotland midfielder had to be replaced by James McCarthy just before the break following a clash with Adam King.

Liel Abada added a second for the Hoops before Conor Sammon pulled a goal back in the second half for the Wasps and although Abada and Yosuke Ideguchi had to go off with injuries and with crucial games against Hearts, Dundee United and Rangers coming up, it was McGregor who caused the Hoops boss the most concern.

“Liel and Yosuke should be OK, Cal’s a significant injury,” said Postecoglou, whose side were drawn at home to Raith Rovers in the next round

“It’s a facial injury, I don’t know what it is but he’s not a great shape. It’s not going to be short-term, it looked quite significant.

“It’s been that sort of season. We have just had challenge after challenge and what we’ve done so far is just get on with it.

“He’s a very important player, not just for what he contributes as a footballer but as a person. I am gutted for him more than anything else.”

Postecoglou insists his side should have secured a more convincing win over the part-time side.

He said: “The main thing in cup competitions is to progress and we did that. We created enough opportunities to make it a more comfortable victory.

“It was a difficult pitch for the way we play. We had quite a few guys getting their first significant game time for a while.

“With all that in mind, it was OK. There’s some mitigating factors so I can’t be too hard on the players.

“The most important thing is we are in the next round.”

With Kyogo Furuhashi out injured and Daizen Maeda set to go on international duty with Japan, Postecoglou was pleased to see Giakoumakis, who has struggled to make an impact at the Parkhead club since signing from VVV-Venlo last summer, get on the scoresheet.

He said: “It was good for him to get a goal. Obviously he hasn’t played much and it was good for him to get 90 minutes and he is going to improve on that.

“At the same time getting a goal is important for strikers and he will improve.”

Alloa boss Barry Ferguson was “proud of the way the boys worked, I thought their effort was different class” and is looking for them to take the positives into the league campaign where they sit in eighth place.

The former Rangers skipper said: “The league form not been good enough. I am not going to sugar coat it.

“I came here at the start of the season albeit a bit late and it was tough to get the players in.

“I missed out on players that I wanted to get who had signed for other clubs. I still think I have enough quality but we need to start winning games.”