The newly-promoted Hatters provided McCann with arguably his stiffest encounter since arriving in South Yorkshire.
Rovers scored early on in both halves and, after weathering a storm, eventually saw out the victory against a stubborn and well-drilled Luton team.
The result means that Doncaster maintain their unbeaten league record at the Keepmoat since McCann walked through the stadium doors in June – two wins and two draws
“We have to try and stay unbeaten at home for as long as we can,” said McCann.
“We’ve only conceded once here (in four games). Against Luton we showed another side to our game.
“When we needed to roll our sleeves up and see the game out we did exactly that.”
Rovers were lucky to go in at the break on even terms such was the visitors’ dominance.
Matty Blair’s superb opener seemed to pale into insignificance from almost the moment it hit the net.
Doncaster were bombarded immediately with wave after wave of Luton attack.
On more than one occasion Luton found joy down the flanks and looked a threat with each attack they mounted.
Inevitably, though, a minute into first-half stoppage time the hosts finally caved in and Elliott Lee nodded in from a few yards out.
However, the hosts came out refreshed after the interval despite the huge downpour that was of biblical proportions.
Less than 40 seconds had elapsed when Ben Whiteman rifled a shot through a sea of bodies to propel the home side back in front.
That was how it stayed, but only thanks to some last-ditch defending from the hosts as they sealed an unlikely win against a team that you would not bet against being in the promotion shake-up come May.
“They were hard to play against,” added Rovers’ manager McCann.
“We’re really showing our steel at the minute.”
Doncaster Rovers: Marosi, Mason, Wright, Butler, Andrew, Whiteman, Kane (J Anderson 75), Coppinger (Taylor 81), Blair, Marquis, Wilks (May 62). Unused substitutes: Lawlor, T Anderson, Prior, Beestin.
Luton Town: Shea, Bradley, Pearson, Potts, Stacey, Lee, Rea, Cornick, Ruddock-Mpanzu, Grant (Jarvis 85), Collins (O’Kane 76). Unused substitutes: Justin, McCormack, Shinnie, Isted, Sheehan
Referee: T Nield (W Yorkshire).