The Bees edged past a dogged Crawley side courtesy of Jonathan Douglas' second-half glancing header as nearest rivals Rotherham crashed to defeat at Sheffield United.
But Warburton insisted the job is not done yet despite seeing his side smash their club-record points tally by reaching 87 with five games remaining.
The Bees were almost totally dominant against an unambitious Crawley side, who mustered just two shots on the home goal all night.
But their resolute defence made Brentford work hard for their chances, and a combination of wayward finishing and good saves from Paul Jones kept it deadlocked until 58 minutes.
Alan Judge got to the byline and whipped in a cross that Douglas headed downwards through the goalkeeper's hand and inside the upright.
Warburton said: "It has turned out to be a good night but there's still a long way to go yet and our only focus now is Swindon on Saturday.
"The players got the rewards for their efforts. They stayed patient and kept to their principles, but the job certainly isn't done yet.
"We have set a target of 94 points because you look at what Rotherham can achieve and have to go one better."