Manchester City moved three points clear at the top of the Premier League after Gabriel Jesus sealed a 1-0 win against Sheffield United on Saturday.
Pep Guardiola's side took an early lead through Jesus's close-range strike at the Etihad Stadium.
City could not add to that advantage against the bottom of the table Blades, but their rock-solid defence nailed down the points with a fifth successive league clean sheet.
"It was amazing that, in this run of 12 wins in a row, still the players run and fight like animals," Guardiola said.
"Sheffield United are a difficult opponent. We said this will be one of the toughest games of the season and it was.
"People think if we won the last game 5-0, we will win this one 5-0. This is the real world, not a fairytale."
Second placed Manchester United were forced to settle for a dour 0-0 draw at Arsenal later on Saturday, leaving City, who have a game in hand on their rivals, firmly in pole position in the title race.
City's winning run is now up to 12 matches in all competitions and they are unbeaten in 19 games since losing to Tottenham in November.
At that stage, it was easy to believe City would struggle to feature in the title race.
But, revitalised by Guardiola's tactical tweaks, they are in the hunt for a third English title in four seasons despite the continued absence of star striker Sergio Aguero.
City's winning streak is the ideal preparation for next Sunday's trip to champions Liverpool, which comes after a visit to Burnley on Wednesday.
"Everyone has to be ready. We are so humble. Ferran Torres and Gabriel Jesus are always thinking about the team. I'm so grateful for them," Guardiola said.
"In December and January to show this consistency is amazing. We will drop points, it's about how we overcome it.
"Hopefully we react well in the bad moments which, for sure, are coming."
- Gritty City -
Guardiola made five changes from Tuesday's win at West Bromwich Albion, with Jesus and Ferran Torres among the players to come in.
That pair played the key roles as City took the lead in the ninth minute.
Torres showed impressive determination to hold off challenges from two United defenders on the right edge of the penalty area as he stumbled to the turf.
Regaining his balance, Torres deftly flicked a pass through to Jesus, who took two touches to get the ball out from under his feet before slotting past Aaron Ramsdale from close range.
The Brazilian striker's sixth goal of the season was his first in the Premier League since early November, ending a nine-game barren run in the competition.
Bernardo Silva should have doubled City's lead when he headed straight at Ramsdale after a mistake from Ethan Ampadu.
For their territorial dominance, City couldn't deliver the knockout blow and Ederson had to be alert to save Rhian Brewster's effort for the Blades.
They kept pushing and Ruben Dias headed wide from Ilkay Gundogan's corner, while Jesus was denied by Ramsdale's block just before he could pull the trigger.
Chris Wilder's team had enjoyed a shock win at Manchester United in midweek and they nearly equalised against the run of play on the other side of the city when Jayden Bogle volleyed over from Oli Burke's cross.
Oleksandr Zinchenko's 20-yard blast was pushed over by Ramsdale before the Blades' goalkeeper repelled Aymeric Laporte's header.
As the tension mounted, John Fleck was inches away from shocking City in the final moments when he volleyed just wide from long range.