The prospect of defeat was almost too much to consider for the Ulstermen, but one that had to be taken into account, such was the form and injury situation at the start of the week. Now, however, McCall is off to four-point start and has his backrow back in harness.
It was a long way from pretty, but the Ravenhill crowd were content just to get the win for the time being. They know that teams in crisis can just take baby steps.
And, a week after one of his worst displays in an Ulster jersey, the man they had to thank for the win was David Humphreys. The outhalf scored all of Ulster's twenty one points with five penalties and two drop goals.
Cardiff may have scored the only try of the match, through Tom Shanklin, but their discipline let them down and Humphreys took full advantage.
Both sides were content to kick for position and try to capitalise on their opponent's errors with the result that, Shanklin's try apart, there was precious little on offer by way of running, fluid rugby.
Humphreys landed his first drop goal on five minutes, but Cardiff had the better of the first quarter, with their pack on top. All they could muster, however, were a couple of long-range penalty attempts from outhalf Lee Thomas that he failed to land. However, he got one on 21 minutes to tie the scores at 3-3.
The game was regularly punctuated by penalties, with Humphreys restoring the Ulster advantage after a midfield obstruction against prop Martin Jones.
Shortly after, Cardiff were down to 14 when a daft mid-air tackle on Andy Ward by hooker Gareth Williams saw the latter in the bin. Ulster took advantage of the situation to tack on another couple of Humphreys penalties to go into the interval 12-3 up.
Cardiff returned pumped up after the break and soon had the only try. Craig Quinnell's lineout charge gave them the impetus, taken on by Rhy Williams, before Shanklin carved through to dot down beside the posts. Given the defensive porousness of recent weeks, this was worrying for Ulster, even more so when Cardiff added the conversion and a penalty through Thomas to go 13-12 in front.
A further penalty apiece was traded by the outhalves before Maggs made the inroads that enabled Humphreys to re-take the lead for Ulster with a well-taken drop goal. 18-16 Ulster, but not safe until Humphreys added a final penalty five minutes from time as the Blues faded, their discipline once again coming back to haunt them.
'The win was everything and the players dealt with the pressure they were under prior to this game incredibly well' said coach McCall afterwards.
Whereas Dai Young, the Cardiff coach, 'thought we were the better team in most departments but the major difference was the penalty count of 18-8 against us'.
Ulster: B Cunningham, T Bowe, K Maggs, P Steinmetz, T Howe, D Humphreys, K Campbell; R McCormack, N Brady, S Best, G Longwell, M McCullough, A Ward (capt), N Best, C Feather.
Replacements: P Shields, R Moore, R Frost, R Wilson, N Doak, P Wallace, J Bell.
Blues: C Morgan; N Walne, R Williams, T Shanklin, J Vaughton; L Thomas, D Dewdney; G Jenkins, G Williams, M Jones, C Quinnell, D Jones, N Thomas, M Williams (capt), K Schubert.
Replacements: A Lewis, R Thomas, R Sidoli, N Budgett, R Smith, N Macleod, S James.
Referee: Joel Jutge (France)