Man City have established an imperious 10-point lead at the top of the Premier League table with Chelsea's challenge faltering in recent weeks.
When asked why that was, Tuchel said: "They did not suffer from Covid as we did over many weeks, so this is a huge difference."
However, as the two clubs prepare to meet at the Etihad in the Premier League this weekend, Guardiola has responded by claiming there is always a reluctance in English soccer to give his players the credit they deserve.
"If they believe it's the reason why then maybe, maybe. Sometimes it's the money that we have, sometimes it's Covid. I don't know. What can I say?
"But the pandemic is all around the world and everywhere there is the virus. We are exposed every single minute and day to getting it.
"We have had a lot of cases and injuries. We played Aston Villa with 11 players in the first team.
"For the last six or seven games we've had four or five Academy players on the bench. We are in the same situation as all other clubs.
"It's not like we are not wiser than others, or because we do the protocols better than the other ones, the virus comes to the bubble and everyone suffers, so we are no exception.
"Today we are OK but in a few hours we might have four or five positives. That is why we have to adapt, adjust, and work out what we have to do.
"The rest, the points we've got so far is down to the quality of the players, this is the main reason why."
Man City were without 21 first-team players and staff for their FA Cup tie with Swindon, but they opted to play the game rather than seek a postponement.
Guardiola, though, says he doesn't really understand the rules surrounding the criteria to call matches off anyway.
"We try to play," said Guardiola, whose side have won their last 11 Premier League matches and avoided any postponements. "If we have 11 or 12 players, it's enough, we play.
"We have Cole Palmer, James McAtee and other players we try to play. We have enough players
"I don't know what counts. Is it just Covid or injuries? Injuries happen all the time so I don't know the rules of the Premier League when it's called off or cancelled.
"In many cases we've had just 12 first team players available plus the keeper and we played."