Chris Sedgwick turned the form-book upside down with his first league goal for 18 months as Rotherham stunned promotion-chasing West Bromwich Albion at The Hawthorns.
Sedgwick, who had not been on target in the league since the opening day of the 2002-03 season, struck after 74 minutes as second-placed Albion crashed to their first defeat in nine home league games.
Rotherham had won just one of their previous eight league matches and had not tasted a success on the road since beating another promotion-chasing side, Wigan, on Boxing Day.
They had to ride their luck at times against Albion but goalkeeper Mike Pollitt was in solid form.
He pulled off a stunning save four minutes from time to preserve Rotherham's advantage when he tipped a free-kick from Jason Koumas on to the bar.
A win would have put Albion level on points with leaders Norwich City, who they play on Tuesday, but they lacked a real cutting edge.
While Albion dominated affairs in the first half they could not find a way past Pollitt.
As early as the first minute he comfortably dealt with a low drive from Koumas and went on to deny Geoff Horsfield, Lee Hughes and Neil Clement.
When Albion did find a way past him, Hughes was unable to keep his third minute shot on target when he crashed his angled drive into the side-netting after a Clement cross.
Pollitt reserved his best save of the half for the 15th minute when he superbly palmed away a Horsfield header after a neat cross from Koumas.
While Rotherham had to play the majority of the opening period in their own half, they still possessed a threat of their own on the break.
They threatened to embarrass their hosts when Andy Monkhouse dispossessed Clement just inside the Albion half 13 minutes before the interval.
Albion central defender Darren Moore was unable to intercept his cross and all he did was to deflect the ball into the path of Sedgwick.
Sedgwick was then faced with only goalkeeper Russell Hoult to beat from the edge of the area but pushed his shot wide.
As Albion's frustration grew, Rotherham's confidence increased and they were only denied an opening goal by the alertness of Hoult six minutes into the second half.
When Ritchie Barker lifted a header into the area it fell perfectly for his namesake Shaun Barker only for Hoult to bravely smother the ball at his feet.
That was a warning Albion failed to heed and they paid the price 16 minutes from time.
Sedgwick picked up the ball 30 yards from goal and weaved his way into the area before beating Hoult with a low right-foot drive.