Beattie pounced either side of the break to complete a hat-trick of Coca-Cola Championship victories for United ahead of the Steel City derby at Sheffield Wednesday later this month.

Brian Howard, a £500,000 capture from Barnsley in midweek, made his debut for the hosts during the closing stages but, predictably, it was Beattie who took centre stage as he confirmed his return to fitness following knee surgery over the summer.

"Beatts' first was absolutely superb," said Blades manager Blackwell. "He showed what he can do if you give him the service.

"When you've got someone like that in your team, capable of putting them away like that, then it can make all the difference. It was a war of attrition in the first half and he broke it."

United paid £4m to secure Beattie's services last season and he underlined exactly why he commanded a club record fee with a superb strike just seconds before the interval.

David Cotterill sent a corner towards Adriano Basso's near post where his team-mate was on hand to power an unstoppable volley beyond the City goalkeeper.

Marvin Elliott spurned a glorious opportunity to equalise soon after and he paid a heavy price for that miss when Liam Fontaine turned Stephen Quinn's free-kick into his own net.

Beattie made the game safe when he converted Cotterill's corner and with Howard showing some good touches after coming on as a substitute, Billy Sharp prodded agonisingly wide as United threatened to run riot.

"We've got to hold our hands up," said City manager Gary Johnson, who led the visitors to the Championship play-off final last term. "We warned the players about set plays beforehand but we didn't deal with them.

"We were second best and there's no point in pretending otherwise.

"This was a key game for us because, if we'd have have taken something from it, then we'd have been a point off from where we were at this stage last year."

The match began in cagey fashion with both teams reluctant to commit themselves forward, and Blades midfielder Quinn's speculative effort from distance was the only meaningful effort of the opening 15 minutes.

When Quinn darted in to meet Sharp's pin-point 23rd-minute cross, Basso prevented the deadlock being broken.

The Blades have been revitalised after their 6-0 mauling at the hands of Arsenal's youngsters in the Carling Cup last month and have been unbeaten since.

City have started where they left off last term with the Robins' only league defeats of the season coming against promotion favourites Birmingham and Wolves.

United manager Kevin Blackwell made two changes to the side which won at Doncaster in midweek as Ugo Ehiogu and Cotterill came in for Chris Morgan and Greg Halford.

Beattie and Sharp spearheaded the in-form home side's attack but they were afforded little space by the Robins' central defensive pairing of Louis Carey and Fontaine.

There were chances for both sides before the break as Carey smashed his volley inches over Paddy Kenny's bar before Cotterill embarked on a mazy run and delivered an incisive ball to the feet of Sharp, but his effort failed to trouble Basso.

But it was striker Beattie who provided the quality to spark the game into life as he met Cotterill's corner with power and athleticism to smash the ball beyond Basso and give his side the advantage going in at the break.

The second half commenced at a rapid pace and the visitors should have levelled as quickly as the 49th minute when veteran striker Dele Adebola's flick-on found midfielder Elliott six yards out, but he somehow conspired to lift his shot over the bar.

Hapless Robins defender Fontaine could then only look on in desperation as his defensive header following Quinn's corner looped over Basso and into the net to double the home side's lead in the 54th minute.

It was soon 3-0 as Blackwell's men established an unassailable lead in the 67th minute.

Once again it was Beattie who proved too hot to handle for the visitors as he battled to rise above the Robins defence and into the net.

Howard came on as the Blades ran down the clock with ease.

Sheffield United: Kenny, Naysmith, Kilgallon, Naughton, Ehiogu, Cotterill (Howard 75), Webber (Dyer 81), Speed, Quinn, Beattie, Sharp. Unused substitutes: Bennett, Jihai, Spring.

Bristol City: Basso, Orr, McAllister, Carey, Fontaine, McIndoe, Wilson (Trundle 59), Elliott, Johnson, Adebola, Akinde (Maynard 65). Unused substitutes: Weale, Noble, Webster.

Referee: K Stroud (Hampshire).