Pep Guardiola praised Manchester City's fighting spirit as the coach collected the 500th win of his career when they beat Sheffield United 1-0.
Gabriel Jesus' strike nine minutes into the clash was enough to secure the three points for the hosts, stretching their winning run to 12 games in all competitions, while they are unbeaten since November.
It was a milestone win for Guardiola, who has won 500 of the 673 competitive matches in which he has managed since he first sat in the dugout at Barcelona in 2008.
"It was so difficult. We knew it would be. It was amazing after this run of 12 wins in a row," he told Sky Sports.
"Still the players run and fight like animals. We conceded one chance at the end. Sheffield United are a difficult opponent. Every time we play them we struggle.
"We said this will be one of the toughest games of the season and it was. The weather is the same for both sides. It’s so difficult because they defend with 10 players. Their team have been together a long time so they know what to do. Nothing is given just because we are blue.
"We started good. We maintained it in the second half. We struggle because they are a very good side. They are alive, you can feel it. They shout, they talk, they stick together until the end."
After beating West Brom 5-0 in midweek, City were expected to make easy work of Saturday's opponents, who sit bottom of the table with just eight points.
But Guardiola insists Chris Wilder's side are stronger than their Premier League record suggests.
"People think if we won the last one 5-0, we will win this one 5-0. This is the real world, not a fairytale," he continued to BBC Sport.
"Today when I see Sheffield is bottom of the league. You see this team and realise how tough is the Premier League. We always struggle to beat them every season.
"It was an incredible performance. We played incredibly well in many areas. We conceded few chances. We didn’t create much but enough to win the game.
"Everyone has to be ready. They are so humble. Ferran Torres and Gabriel Jesus are always thinking about the team. I’m so grateful for them."
He added: "In December and January to show this consistency is amazing. We will drop points, it’s about how we overcome it.
"In this league every game is so difficult. Hopefully we react good in the bad moments which for sure are coming."
