The defender made his return to league action off the bench in the midweek win over West Bromwich Albion and followed it up with an assured display against the Blades as Guardiola's side kept an eighth clean sheet in 10 league games.
“I am happy Aymer is back," said the City boss. “He played really well.
“It's not just Ruben [Dias] and John [Stones], it's everyone - Nathan [Ake], Aymer, the full-backs, Joao [Cancelo], Kyle [Walker] and Oleks [Zinchenko]."
City were comfortable for long periods against Chris Wilder's side, who were resolute in defence and limited our chances in the final third.
Guardiola admitted the visitors made life tough for his team, but he was pleased with the effort he saw from his players.
“Today I see the team [Sheffield United] is there," he added.
“They stick together, fight, complain about decisions - when you see a team like that you know always how difficult it will be.
“Today we concede few and did not create much, but I give credit to the opponent. It wasn't because we weren't good. I am more than pleased."