Magomed Ozdoev thumped home from long range and Aleksandr Golovin slotted home from 10 yards as Scotland endured a second successive 4-0 loss.

Clarke has now suffered four defeats in his five games in charge and Scotland sit fifth in European Championship qualifying Group I, four points adrift of Cyprus in third.

When asked where it had gone wrong, Clarke said: "We conceded a soft goal. The first goal is soft, from a corner. Man on man we have to do better.

"From there we quickly found our way out the game. We allowed the game to run away from us.

"I have to put it down to fragile confidence. The players seemed to lose heart very quickly, which is unfortunate because we had done OK up to that point."

With a top-two finish all but impossible before Scotland kicked off in the Luzhniki Stadium, Clarke had been looking to start building for the play-offs in March.

When asked how he builds Scotland up with just three games left, he said: "Hard work, maybe one or two different selections in terms of squad as well as starting 11. We can't keep conceding goals.

"You have to give a nod of your head to the quality of opposition we have faced recently in Belgium and Russia, two very good teams who I am sure will be involved in the latter stages of Euro 2020.

"But for us it's trying to make sure this is the very, very bottom of the lowest and then build from here and make sure come March we are able to be very, very competitive and get through the play-offs and give ourselves the chance to be in the same championships."

The former Kilmarnock boss added: "In all the games we have played there have been moments where you can see what we are trying to do and where we are trying to get to.

"But listen, the results are dreadful, there is no getting away from that.

"We have to do better, we have to work harder and we have to make sure as a group of people working together that we keep improving. And we have to make sure this is the lowest of the low."

Russia head coach Stanislav Cherchesov gave his opinion on how the game had changed.

"I told the players at half-time – and before the game but they didn't listen – that we shouldn't pass the ball too much in the middle of the field, just send the ball to areas where there was danger," he said.