The Spaniard was quoted by Sky Sports as he commented on United's swap deal for the Chilean involving Henrikh Mkhitaryan, admitting that the Chilean has the right to decide his own future.
City were thought to be favourites to land Sanchez but pulled out of negotiations over his transfer due to Arsenal's monetary demands.
And Guardiola now wants everyone associated with City to move on as he wished both United and Sanchez luck in their new working relationship.
He said: "I am not the guy with the mathematics, the numbers. What I know right now is Alexis is still an Arsenal player. I think he is going to go to United so congratulations to both of them.
The Henrikh Mkhitaryan-Alexis Sanchez deal is a straight swap deal, there is no cash in the transfer. Please stop listening to the figures Twitter accountants are making on their calculators.— Adam Joseph (@AdamJosephSport) 18 January 2018
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Pressed further on the issue by the assembled press, Guardiola explained why he did not feel let down by the player he had managed at Barcelona before Sanchez left to move to north London.
He continued: "My opinion of Alexis remains the same. It was a pleasure to be with him at Barcelona and he is going to decide to move onto another club. I wish him all the best."
City face an injury crisis at left-back with Fabian Delph joining Benjamin Mendy on the sidelines after he limped off in last Sunday's 4-3 loss to Liverpool.
Fabian Delph looks to be out for tomorrow's game against Newcastle so Zinchenko might be bought in to the squad— peterlegerton (@Beanheadz98) 19 January 2018
Guardiola admitted it may be difficult to find a suitable replacement for the duo, but added that he would have to make do with whoever was available to him in that position.
He said: "We have a problem [at left-back] for the next few weeks. We have had a problem since the start of the season because we decided to start the season with just one full-back. We hadn't options to buy because we spent enough money.
"We knew that and now the problem with Fabian Delph, we are going to see how we solve the problem, because it is not for just one or two games. It will be for longer.
"In this kind of situation, it depends on the mentality of the players. If they are able to make a step forward and some players play in not natural positions, and other guys help them, everything is going well."