Four straight home wins is probably enough evidence to suggest Derby have the stamina to maintain their Championship play-off charge.
Back-to-back 1-0 wins in the past week have also underlined their capability to be a resilient and durable team.
However, they ought to have beaten Birmingham by more.
The January addition of Sammie Szmodics and the return from injury of Carlton Morris means John Eustace has an attacking armoury to rival any other side in the play-off race.
At the back, 37-year-old goalkeeper Richard O’Donnell – Blackpool’s second-choice last season in League One – looks wily and assured as he continues to deputise in the absence of both Jacob Zetterstrom and Josh Vickers. Centre-back Matt Clarke appears to be able to head the ball as well as any defender in the division.
Derry Murkin – another of Derby’s mid-season acquisitions – brings balance and athleticism on the left.
The Rams had boundless energy on Saturday and the home fans appeared to appreciate that alone. This latest impressive showing indicated Derby are at least a force to be reckoned with in the promotion race.
