Maguire was twice guilty of losing possession in risky areas but the incident which cost the Three Lions was down to a moment of madness from Kyle Walker, whose swinging arm caught Fakh Ben Youssef.
Not after Kane got England off to a flawless start with an 11th-minute tap-in.
And 10 minutes before half-time England were punished for wasting chances as Roldan ruled Walker had intentionally made contact with Ben Youssef, Sassi's penalty powerful enough to beat the fingertips of Jordan Pickford and find the bottom-left corner.
"At 1-1 we had a plan to. keep probing but not get caught on the counter-attack", said England manager Gareth Southgate. But England struggled to finish it off. Tunisia looked more comfortable as they sat back in defense, only to be undone by Kane in the 91st minute.
"We could have had a couple of penalties, especially when you look at theirs", Kane said.
The Tottenham Hotspur striker bookended a heroic performance and scored either side of a Ferjani Sassi equaliser from the penalty spot, netting a 91st-minute victor as Gareth Southgate's side clinched three points in shaky fashion. Maybe it was a bit of justice to score at the back post at the end. That's football, that's the ref. "It showed good character to get on with it".
After Belgium thrashed Panama 3-0 in the other Group G game on Monday, the pressure was on England to deliver only their second win in their last nine games at World Cups.
It's only too fitting that Kane was the example to follow then.
He added: "I was most proud of the way we kept playing even though the clock was running down".