A STUNNING four-star second display saw Barnsley end August on a scintillating high to take the derby spoils in eye-catching fashion against the chastened Millers at Oakwell.
After a decent enough first-half, Alan Stubbs' side were second best in a disastrous showing on the restart, with the Reds upping the ante to claim their third successive home win on the return to the second-tier in powerhouse fashion.
By the end, the hosts were carving open the visitors almost at will, with the Millers being thoroughly browbeaten and receiving some justifiable boos from the 3,293 away contingent at the final whistle.
A close-range strike from Marc Roberts forged the breakthrough and Adam Hammill's deflected low shot, which went in off Kelvin Wilson, doubled the Reds' advantage on 57 minutes.
The gloss was provided late on, first by Reds substitute Tom Bradshaw, with the striker - courted by the Millers earlier in the summer - heading home his first goal for the club four minutes from time.
There was still time for Ryan Kent to seal a fine show with a clinical fourth before the end.
The win provided a spot of karma for the Reds, edged out in the derby stakes against Huddersfield Town last weekend, while the Millers' wait for a first win at Oakwell since August 1970 was extended.
Barnsley were forced into one enforced change with Angus MacDonald handed his debut ahead of the impending completion of Alfie Mawson's big-money move to Premier League outfit Swansea City.
A welcome sight was the return to the starting line-up of last season's top-scorer Sam Winnall, in place of Bradshaw..
Meanwhile, Andy Yiadom stepped in for James Bree at right back.
The Millers made just one change, with Jake Forster-Caskey coming in for the injured Tom Adeyemi.
A competitive first half saw both sides afforded encouragement, although clear-cut chances were at a premium.
Winnall saw his downward header flash wide early on after Yiadom's cross, while the hosts' best other moment saw Adam Winnall twist and turn before seeing his well-struck shot beaten away by Lee Camp.
In the main, defences were on top, with the Millers, fielding a 4-2-3-1 formation, producing a much more sound away performance following on from difficult experiences at Aston Villa and Brighton, with Izzy Brown and Paul Taylor both looking lively on the flanks.
In the home goal, Adam Davies was protected well enough, with Mark Roberts and new man MacDonald acquitting themselves well.
A couple of moments of danger saw Forster-Caskey shoot at Davies and Taylor's cross-shot flashing across goal, with no visiting player able to get the finishing touch.
After a fair away showing in the first period, Alan Stubbs had encouragement to mull over at the top, only for his game plan to be obliterated inside 12 second-half minutes as Barnsley made capital following a poor start to the second half for the visitors.
The warning signs were there early on when Lee Camp made a fine instinctive save to turn away Conor Hourihane's goalbound strike.
The Millers failed to liven up with Barnsley suddenly scenting blood.
An opener duly arrived on 54 minutes when United failed to deal with Hammill's swinging free-kick and amid the consternation, Roberts stabbed the ball home from close range at the near post.
Soon after, the Reds doubled their money following a quick-fire break, with Hammill cutting inside in trademark fashion before seeing a low shot fly into the net, via a significant deflection off Kelvin Wilson.
All the Millers could muster with a low shot from Taylor, which was held by Davies, with the Reds being the ones to pose the questions.
Kent soon saw a strike deflected over with the Reds needing no second invitation to hit the Millers on the break.
The only downside for the Reds came with substitute Stefan Payne, just four minutes after entering the fray for Winnall, having to be forced off with a hamstring issue, with Bradshaw replacing him.
In general play, it was comfortable in the extreme for the Reds, with Kent testing Camp's reflexes before Hourihane saw his shot held.
At the other end, the Millers lacking the ingenuity or quality to make an impression in the final third.
A late header from Bradshaw sealed a sweet derby day for the Reds and worse was to come with Kent firing high past Camp after being played in by Hourihane.
Barnsley: Davies, Yiadom, Roberts, MacDonald, White, Kent, Scowen, Hourihane, Hammill (Lee 88), Winnall (Payne 69 (Bradshaw 72), Watkins: Substitutes unused: Townsend, Moncur, Evans, Tuton.
Rotherham United: Camp; Fisher, Ball, Wilson, Kelly; Forster-Caskey (Yates 65), Vaulks; Taylor (Newell 80), Allan, Brown (Forde 83); Ward: Substitutes unused: Price, Mattock, Wood, Smallwood.
Referee: G Scott (Oxon).
Attendance: 15.293 (3,293 Rotherham fans).
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