A second half brace from Will Grigg propelled Brentford to their first win of the Sky Bet League One season.
The Bees dominated for long periods against Sheffield United and went in front through Adam Forshaw.
But the visitors found a response after the break and were level by the hour mark.
That was, however, the cue for Grigg.
The striker, signed from Walsall in the summer, fired his first Brentford goal home soon after United had levelled and then followed up to score a third after a Forshaw shot was saved.
George Long, in the Sheffield United goal, was responsible for keeping the score down and he saved a Grigg penalty late on as the striker sensed a hat-trick on his home debut.
But there was nothing he could do at the other end and Brentford recorded a 3-1 win against one of the team expected to challenge for promotion.
Brentford started brightly, moving the ball better than their hosts and dominating the early territory.
The visitors were trying to play the ball put from defence and utilise what was effectively a five-man midfield.
However, the odd passing error gave Brentford possession in key areas and didn’t enable them to get much of a foothold in the game.
There were not many chances in the first 30 minutes, but Brentford had them all.
Forshaw shot narrowly over with his left foot when the ball dropped loose on the edge of the penalty area and Clayton Donaldson’s near post flick from a Jake Bidwell cross was deflected narrowly wide.
United’s first sight of goal came when Lyle Taylor controlled a long harry Maguire pass but David Button was out smartly to prevent him making any more of it.
At the other end, Neill Collins made a vital tackle to prevent George Saville finishing off a Forshaw cross and moments later Brentford were ahead.
The goal came when United right back Darryl Westlake went darting up the field and lost possession, Michael Doyle tried to fill in but made a mess of a clearance and Saville had yards of space, he fed Forshaw in the inside left channel and with the freedom of Griffin Park he curled a shot in to the top corner from 20 yards.
United could have equalised when they found space in midfield, Conor Coady fed Lyle Taylor and the striker shot over from 18 yards when he should have tested Button.
But Brentford built on their goal and set about putting the game out of sight.
Conor McAleny miss-hit a volley from an Alan McCormack cross and goalkeeper Long made a fine low save to keep out a Forshaw drive.
The Bees came flying out of the blocks in the second half – Long made a brilliant low save to keep out a McAleny snap shot after a superb move involving Donaldson, Forshaw and Shaleum Logan.
McAleny forced the goalkeeper to save at his feet after McCormack darted in to the box and then curled a shot wide.
But United started to regroup and they got a foothold early in the second period.
Button made a save from Febian Brandy and Bidwell made a vital tackle to prevent Coady turning in a Marcus Williams cross.
The first corner won from that Bidwell clearance was dealt with but the second was delivered by Stephen McGinn and Neill Collins rose completely unmarked to head the visitors level.
They were not, however, level for long.
Saville got the better of McGinn on the left side, outmuscling the midfield man in the right back position, and cut the ball back for Grigg to fire unerringly in to the bottom corner and restore Brentford’s advantage.
Long made a fine low save to keep out a Saville shot after McAleny broke away and Button made a simpler one at the other end from a Brandy effort.
Long saved a Donaldson header and did the same moments later while a Forshaw shot was blocked.
Brentford made the game safe with 14 minutes remaining when Forshaw darted through a gap that didn’t really exist and twisted Maguire inside out, his low shot was saved by Long but Grigg was quickest and tapped in to make it 3-1.
The striker was buzzing now and won himself a penalty when he turned away from Maguire and was brought down by the central defender.
Grigg stepped up and his penalty was aimed for the top corner but Long went away to his left and kept it out.
United tried to build on that and respond at the other end but had little to offer.
Button saved a weak shot from Brandy and the small attacker then headed over while Saville had a shot blocked at the other end and curled a free kick over the bar.
Brentford continued to press forward in the later stages but had done more than enough to take the points and get their first win of the League One campaign.
Brentford: Button; Logan, Dean, Craig, Bidwell; Forshaw, McCormack (sub Reeves 77 mins), Saville; Donaldson, Grigg (sub El Alagui 85 mins), McAleny (sub Fillo 68 mins)
Subs (not used): Bonham, Venta, O’Connor, Saunders
Bookings: Saville (20 mins)
Sheffield United: Long; Westlake, Maguire, Collins, Williams; Doyle, McGinn (sub McFadzean 74 mins); Brandy, Coady, Murphy (sub Porter 74 mins); Taylor
Subs (not used): Howard, Hill, Flynn, McGinty, Whitehouse
Bookings: Westlake (44 mins), Coady (83 mins), Williams (87 mins)
Attendance: 7,316 (1,270 away fans)
By Chris Wickham