The Northern Irishman made six changes - five of which were enforced - to the starting XI that lined up against Portsmouth last time out, but the Tigers still had far too much in their locker for a lacklustre Addicks outfit.
A number of City players tested positive for Covid-19 in late December, leading to the postponement of Tuesday's clash with League One promotion rivals Lincoln as individuals were forced into self-isolation.
First-choice goalkeeper Matt Ingham was only fit enough for the substitutes' bench having contracted the virus, while forwards Josh Magennis and James Scott plus defensive duo Reece Burke and Callum Elder - all also assumed to be suffering from Covid - missed out altogether.
This led to George Long, Alfie Jones, Brandon Fleming, Hakeeb Adelakun and Tom Eaves being selected from the start, while the influential George Honeyman took over from Regan Slater in midfield having recovered from injury.
Yet, despite the absence of a host of key men, City impressed at both ends of the field as they climbed one place to second in the league table, leading McCann to hail the professionalism of his players in trying circumstances.
"It's been difficult. We went into the game without five players who started the last one, so it's testament to the squad depth and the lads' focus on getting the job done," Hull's head coach said.
"It's not been easy not seeing each other for 10 days, it's been difficult to try and prepare. It's never easy when you can't see them, apart from on a screen, but the boys' professionalism has been unbelievable.
"The last two days in training is probably the best I've seen the group train and I was a bit worried coming into the game because sometimes you can have two good training sessions and not perform in the game.
"But, I thought we did today, against a team who I've no doubt will be around the top end of the league come the end of the season.
"We coped with everything they threw at us and looked a real threat at the other end so I'm really pleased with the result."
Goals from Adelakun and Greg Docherty fired the Tigers to their first success in five league outings, and while McCann dismissed any notion that this weekend's win was pivotal in terms of his team's promotion hopes, he conceded that a three-point haul was certainly welcome.
"It was important that we got back on track," he added.
"There’s a lot of football to be played, but today was important for us to get back on the horse, back on the winning trail and get that confidence back into the group."
Victory sees City leapfrog Portsmouth in the League One standings and leaves them four points shy of leaders Lincoln, with a game in hand.