CHALLENGING on so many fronts is enjoyable – and a bit like a high-wire act.

If your squad is used to it and has the depth and resources of a Manchester United or Chelsea, it’s nothing unusual and not as fraught.

But when you are a season-and-a-half out of the Championship, battling for survival with a momentous occasion on the horizon, and the possibility of another, it’s a stern test of durability and resolve.

Alex McLeish made the point after Blues swept into the FA Cup quarter-finals that he was concerned about the side effects of league, Carling Cup and FA Cup exploits.

Taking a fatiguing toll on the legs and minds was a worry for Eck, which impacts on results and availability.

Already, Scott Dann and James McFadden have had to be classified as long-term absentees.

Martin Jiranek and Liam Ridgewell were not fit for Saturday’s fifth-round tie, Curtis Davies was also sidelined and Cameron Jerome was withdrawn at half-time after going over on his ankle.

And Aleksandr Hleb was possibly kicked out of Sunday’s final by a poor tackle from James O’Connor that should have been punished by a red, not yellow, card.

McLeish used the tie against Sheffield, who haven’t won in League One since December, to rest some who needed a rest – with an eye on the Carling Cup final – and to encourage others to potentially stake their claim, and get some match sharpness.

It could well be that after the final he will have to look more closely at rotation, and utilise all the numbers, even substitutes more often for longer.

Even though they dug out fine recent results in the Carling Cup semi-final and league, there have been signs that this season – a more troubled and less straightforward one than last all told – has been catching up with Blues.

The Newcastle United defeat ended an anti-climatic game too far for Blues after the sterling stuff that had gone on in the immediate weeks prior.

Conversely, the team McLeish fielded against Sheffield had too much about them to ever be seriously in danger of an upset. The players who have been itching for further involvement were sure, sharp and ultimately professional.