But the reigning champions were made to battle for it before second-half goals from Sergio Aguero and Kevin De Bruyne.
It meant Guardiola had reached his century in only 134 matches, beating Jose Mourinho to the mark by eight games and Jurgen Klopp by 25.
“This achievement is a compliment for the club, the staff,” Guardiola said.
“One hundred victories in 134 games, only 34 where we (didn’t win), it is an incredible achievement for this organisation, for all the staff and the people who did it.
“I’m alongside prestigious managers and clubs, and City is there and in front of them and that means what we have done in three seasons is incredible.
“Especially in the Premier League where you have to be consistent, we are all delighted with this achievement.”
The 100th did not come easily against a Blades side who edged the first half, seeing a Lys Mousset strike chalked off by VAR for a marginal offside, while they had complaints about Aguero’s opener after referee Chris Kavanagh appeared to impede John Fleck in the build-up.
“Today I realised – I already knew it but when you experience it yourself it’s better – why Sheffield (United) are in the position they are in and didn’t lose one game away,” said Guardiola.
“It was an incredibly tough game because we played after less than 48 hours one of the most physical teams in the Premier League and we won it so a big compliment for the team again.”
Chris Wilder joined the list of managers left to grumble about VAR on another weekend of controversy in the Premier League, noting that even the City fans had joined United supporters in chanting against the technology during the first half.
“Up and down the country you hear it, a four-letter word before VAR,” he said. “These are proper football people.”
Wilder declined to reveal the nature of a conversation he had with Kavanagh in the referee’s room after the match but, if he was unhappy with the officials, Wilder was proud of the performance his players put in.
“If you are going to lose, there’s a way to lose,” he said. “But I’ve seen my team and the run we’ve been on. Did we think we’d take it to the back end of December? I don’t think so.
“We’ve grown in confidence and belief. It’s a great learning curve. They’ve got unbelievable players here. The two clubs are light years apart. They weren’t 20 years ago.
“One club didn’t move forward at the pace that City have, but I didn’t think the gap was unbelievably visible in terms of the tightness of the game. My team gave it a go and that’s the basic remit we have.”