Erling Haaland scored a vital winner 19 minutes from time as Manchester City eventually broke Brentford's stubborn resistance to close to within a point of the Premier League summit.
What looked set to be a night of frustration at Etihad Stadium for Pep Guardiola's men turned on a moment of huge fortune.
Brentford defender Kristoffer Ajer appeared to have the situation under control when Julian Alvarez played a pass into the visitors' half as City countered.
But as Haaland began the chase, Ajer slipped and could not regain his feet as the Norwegian sped past.
The 23-year-old kept his cool to beat Mark Flekken with a precise shot. It was Haaland's 22nd goal of the season and means he has now scored against every Premier League opponent he has faced.
More importantly, it secured a victory that took City above Arsenal into second spot and kept a record fourth consecutive title in their own hands given they still have to visit Liverpool on 10 March.
While the result was not exactly harsh on Brentford given City's dominance, the manner of it was unfortunate. Thomas Frank's side were much more organised than they were in the heavy defeat against Liverpool at the weekend.
However, with six points from their last 11 games, they are only five points off the relegation zone and still searching for the sustained improvement that will get them away from trouble.