The Blues have lost prop Alex Hodgman to an arm injury, with Sione Mafileo travelling as a replacement, but their entire squad showed such form at Ellis Park, including, significantly, their reserves, that Hodgman's absence shouldn't be an issue.
The Blues bench brought them home, and that's something Umaga will cherish for he hasn't got enough from it during his two full seasons at the franchise.
It was replacement loose forward Murphy Taramai who scored the winning try near the posts in the final minute. Four minutes earlier it was another replacement loosie, Jimmy Tupou, scoring, with reserve lock Scott Scrafton playing his part in the build-up.
And Stephen Perofeta's influence in those final, frantic, minutes, cannot be stressed enough. The 20-year-old replaced first-five Bryn Gatland with 25 minutes remaining and brought a Dan Carter-like calmness to his team.
Perofeta, playing his first competition game of the year after returning from a hand injury, displayed a computer-like ability to take the right option and he has the golden knack of creating time and space for himself without seeming to do anything special at all.
He will probably be Umaga's main selection issue this week, and it wouldn't surprise to see Perofeta starting in the No10 jersey at Newlands.
He started the year as the top-ranked first-five at the franchise and is likely to have done enough to prove his fitness for what is an extremely important fixture for the Blues. A win in Capetown would represent Umaga's most significant fortnight at the franchise.
His best result so far was watching his men beat the British and Irish Lions at Eden Park last June. Their next result was a thrashing at the hands of the Sunwolves in Tokyo.
It's time for them to live up to expectation.