Ferguson putting a run of games together is a crucial ingredient to Everton avoiding a brush with the drop. There can be no more daunting sight for even the most strapping of centre-halves than the fearsome Scot going full-throttle.
There are not many who could claim to play him well, the only problem being that not many have had to play him at all since his return to Everton following an injury-ravaged spell at Newcastle.
Ferguson opened his account for the season at Charlton on Saturday with a penalty as Everton put three points on the board as an early-season marker of intent. And the big fella certainly gave his boss a boost.
"Big Dunc is a threat to any team when he is up and playing," insisted Smith. "He has had a lot of pre-season training and he is as fit as he has been for two years."
The Blues boss was understandably delighted to get off the mark on the very first day of the new Premiership campaign, the first Everton manager to do so since Joe Royle in 1996, and he felt that the side were full value for the three points.
"I thought we deserved our win today, no-one can argue against that," he said. ""Most of our play throughout the 90 minutes was exceptional. But I thought at one stage after we had had a lot of pressure, missed a lot of chances and gone behind, we could have folded."
After a close-season during which Everton manager had to endure the departure of livewire striker Francis Jeffers to Arsenal, fitness bulletins regarding Goodison favourite Duncan Ferguson must have been of some comfort to the often beleaguered boss.