Doku's goal opened the scoring against the stubborn Bees, cutting inside and curling in a delightful finish just as he did to rescue a last-gasp draw at Everton on Monday.
The 23-year-old has now scored four important goals in his past three games - the strike against Brentford, the double at Hill Dickinson Stadium and his effort against Southampton to help City into the FA Cup final.
In fact, he has seven goal involvements in his past six games - with five goals complemented by two assists - as many as in his previous 24.
"If you want to become a better player, you have to win games for yourselves," said boss Pep Guardiola. "It is not enough to make good crosses for the other ones, you have to win games and score goals.
"At Everton, the goal for 3-3 was the right [foot], but the first goal was the left. He made an incredible step in that sense to say 'I'm Jeremy Doku, I'm going to win games'. The big players always have that mentality."
Doku told BBC Match of the Day (MOTD): "I'm an instinct player. Today it's working out. I scored some goals, I've always played with instinct but now the goals are coming.
"I haven't been a different player."
'Best we've seen of Doku'
Manchester City's challenge may depend on Doku continuing to produce moments of brilliance to drag his side towards the finish line.
He has scored in three successive appearances in all competitions for the first time in his Manchester City career.
On Saturday, the winger gave Michael Kayode a taxing time, twisting the Brentford full-back inside and out throughout the game, and he could have scored in the opening two minutes but was thwarted by Caoimhin Kelleher.
Q&A
How did Manchester City perform against Brentford?
Manchester City won 3-0 against Brentford, maintaining their chances in the title race.
What did Jeremy Doku say about his performance?
Jeremy Doku mentioned he needed to add more goals to be considered among the best wingers in the world.
Is Jeremy Doku a key player for Manchester City?
Yes, Jeremy Doku's recent performances have been crucial in keeping Manchester City competitive in the title race.
What impact does Doku's scoring have on Manchester City's title chances?
Doku's scoring ability is vital for Manchester City's success and their pursuit of the title this season.
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His performance was widely praised, with MOTD pundit Ashley Williams saying it is "the best we have seen of Jeremy Doku".
The former Wales international defender added: "From a defender's point of view, I am not sure I would know how to stop him. He is physically strong, can go right or left, his acceleration is something else but also his deceleration can leave you flat-footed.
"He was up against Kayode, who I really rate, and he just couldn't handle him. He has been the best player in the Premier League these last few weeks."
Former City striker Daniel Sturridge said on Sky Sports: "He has been exceptional. The goal he scored in this game was a thing of beauty. It is a brilliant finish.
"That is the go-to finish for him now. The repetitions in training are paying off. His game is progressing, he is becoming more decisive in those moments.
"Confidence is key for attackers, it is the most important thing. If you doubt yourself at any time you won't make the difference. Now he is thinking 'I can do this, I can score'."
Doku's brilliant showing made him just the third player in the Premier League this season to create six or more chances and complete six or more dribbles after Bukayo Saka and Elliot Anderson.
"He is a top player," said Brentford boss Keith Andrews. "If it's not Doku, then someone else will step up and that is the luxury Pep has - phenomenally talented players, game changers who can decide games and that is ultimately what happened with the first goal."
Doku dedicated his latest goal to his dad, who turned 60 on Saturday, saying: "It's his birthday.
"I am becoming a dad soon and he sacrificed his life for me every time, bringing me to the club not knowing I would be what I am now.
"For me that's a big thing so him turning 60, I am grateful and that is why I wanted to give this goal to him. Having him around is a blessing."
Figure caption,
Scoring goals isn't to be a genius, it's to bring players close to Haaland - Guardiola
'Come on you Irons'
The general feeling is that this season's title race hinges on Arsenal's trip to relegation-threatened West Ham on Sunday.
Should Mikel Arteta's side emerge victorious, the trophy is theirs to take with two games remaining.
Those matches are against already-relegated Burnley before finishing the season against Crystal Palace, who have a Europa Conference League final to negotiate.
However, if Arsenal draw or lose against the Hammers, it leaves the door ajar for City once more, with fixtures to come against Palace and Bournemouth before rounding off against Aston Villa.
Asked if he will watch Sunday's match, Guardiola told BBC Radio 5 Live his sister is visiting as he has "not seen her for a long time" but if he is at home "of course I will take a look and watch - I like football".
Haaland, meanwhile, took his tally to 50 goals for club and country and said the players "can't think of the title race", but he will have "notifications on his phone" of the Arsenal-West Ham game.
Guardiola ended Saturday's post-match news conference by saying "come on you Irons", before gesturing the Hammers symbol with his arms above his heads.
The Spaniard knows his side need a favour from Nuno Espirito Santo's men to maintain hope.
