Bryan Robson won his tactical battle with opposite number Alan Pardew as United recorded a first victory at The Valley since 1971.

In United's promotion season of 1970-71, goals from Alan Woodward and Billy Dearden secured a 2-0 victory but on Tuesday night the current Blades went one better thanks to strikes from James Beattie, Michael Tonge and Chris Armstrong.

Boss Robson switched to a 4-5-1 formation and a hard-working performance allowed the Blades to weather an early storm before registering three more points in this rollercoaster season.

For the trip to The Valley, boss Robson made two changes, albeit one enforced with Bennett failing to recover from a hand injury sustained at the weekend, allowing Kenny to reclaim his place in goal. The second of the changes saw Tonge replacing Webber, indicating the formational change.

There was danger for United within the opening 60 seconds when Sodje got away from Kilgallon but headed Reid's set-piece wide, whilst the Blades also won two corners in the opening minutes.

Robson was quickly at the front of his technical area waving his defenders forward in an attempt to counter Charlton's fluid attacks. Iwelumo was obviously the focal point of the home side's attacks but the likes of Thomas, Reid and Sam displayed good movement. It was the latter who twice tested Kenny within the space of a minute. Firstly, Sam got the better of Carney and then did the same to Naysmith but the United goalkeeper was well positioned.

Kenny was called upon again moments later, racing off his line to clear Naysmith's short back-pass ahead of Sam, who was Charlton's brightest light early on and he shot at the goalkeeper yet again on 20 minutes.

Naysmith made amends for his earlier minor error with a timely tackle on Sam in the penalty area but United were beginning to get a foot in the door, with the high defensive line undoubtedly helping.

The Blades delivered a number of crosses into Charlton's box but all were wayward or away from the intended targets. Carney's corner caused problems for Weaver, under pressure from Cahill, and although the home side survived, they were not so fortunate moments later.

From Bardsley's deep cross, Thomas inexplicably barged into Carney and referee Halsey had little doubt in his mind, awarding United a penalty. BEATTIE added to his goal tally by firing beyond the right hand of Weaver from 12 yards.

As the half progressed Tonge was seeing more of the ball and he latched on to a Gillespie pass before cutting in and testing Weaver from the edge of the box. United continued to attack and from a Beattie knock down, Carney showed good technique to get a powerful shot on target but the ball cannoned off the shins of Mills with Weaver scrambling across his goal.

Two minutes of added time was indicated and the home side forced the final set-piece of the half but from Reid's delivery, Montgomery epitomised the midfield's desire to protect the defence by decisively heading clear.

Charlton chief Pardew was obviously unhappy with his side's first half showing and made a double change at the break, introducing Holland and Varney, the latter joining Iwelumo in attack.

It had the desired early effect as the home side made a bright start and from Reid's free-kick a glancing header from an unmarked Varney was wide of Kenny's right post.

Twice in the space of a minute, Kenny's goal was put under pressure again. Firstly, on 57 minutes, Thomas delivered a cross and Iwelumo's header was wide with Kilgallon in close proximity, whilst the big striker linked up with Varney, who mis-hit an effort wide.

With 62 minutes gone, Beattie had a second disallowed, rightly so, when he was standing in an offside position when he turned Montgomery's screwed shot into an empty net after good work by Gillespie, but the home side fought back.

Just two minutes later, Kenny spilled a shot from Mills but recovered to make a superb second save from Varney close in and then Reid's free-kick was deflected over by the wall after Montgomery's foul on Holland.

Pardew used his third substitution midway through the half, sending on Bougherra at right back and switching Mills to the left and it was the latter who set up Charlton's next chance, on 70 minutes, when he allowed Varney to deliver a cross behind the defence but Zheng Zhi's first-time effort struck the top of the crossbar and flew into the home fans behind the goal.

United, however, relieved some of the pressure on 75 minutes, although there was initial confusion of who had netted the second goal. From Gillespie's corner, Sodje failed to clear and CAHILL poked home in a crowded penalty area. It took a nervous moment before referee Halsey awarded a goal and Mills led Charlton's protests and was cautioned for his trouble.

There was still defending to do and United's midfield again backed the defence to repel the Addicks. In fact, it was from a Charlton attack that the Blades claimed a third goal, with just a minute of normal time remaining.

Kilgallon began the breakaway with a clearing diving header and after Beattie had got the better of Sodje, he laid off for ARMSTRONG to fire past Weaver with his favoured left-foot and allowed the United fans behind the goal to engage in some banter with Charlton's Sheffield Wednesday-supporting goalkeeper.

Three minutes of added time was comfortably negotiated to enable United to secure fourth game unbeaten on the road.

Charlton: Weaver, Mills, Basey (Bougherra 66), Fortune, Sodje, Sam (Varney 45), Reid, Samedo (Holland 45), Zheng Zhi, Thomas, Iwelumo. Unused: Randolph, Ambrose.

Blades: Kenny, Naysmith, Bardsley, Beattie, Carney, Kilgallon, Montgomery, Tonge, Gillespie, Armstrong, Cahill.
Unused: Bromby, Stead, Webber, Gerrard, S. Quinn.