Sheffield Wednesday striker Chris O'Grady dumped Premier League hopefuls West Ham out of the FA Cup with a thumping late strike at Hillsborough.
O'Grady slammed past Hammers keeper Ruud Boffin from 12 yards with only three minutes of normal time remaining.
Gary Megson's side were also indebted to goalkeeper Nicky Weaver, who saved Sam Baldock's second-half penalty.
Weaver also tipped a Baldock strike on to the post before O'Grady put the League One side into round four.
Both clubs have a rich history in the competition having lifted the famous trophy on six occasions between them, but there has been little for either set of fans to cheer in recent years.
Wednesday have plummeted to the third tier and the Hammers are dealing with life in the Championship - only six years after a penalty shoot-out defeat by Liverpool in the 2006 final .
With both sides sitting second in their respective divisions, Megson and Hammers boss Sam Allardyce have admitted that winning promotion is their main priority, though the Owls manager will be proud of his team's display against the Championship high-fliers.
However, Allardyce will be left ruing Baldock's failure to convert from 12 yards before Weaver's fingertip save pushed the former MK Dons striker's angled shot onto the woodwork.
Having used the game to give run-outs to several of his fringe players, Allardyce may not have been surprised to see a lack of fluency from his much-changed team in the first half.
And his side should have been behind when Owls attacker Jermaine Johnson spurned a golden opportunity for the hosts.
OWLS AND HAMMERS FA CUP WINS
- 1896 - Sheffield Wednesday
- 1907 - Sheffield Wednesday
- 1935 - Sheffield Wednesday
- 1964 - West Ham
- 1975 - West Ham
- 1980 - West Ham
The Jamaican did everything right as he cut inside the West Ham defence but, as stand-in Hammers keeper Boffin went to ground, he somehow missed the target with the goal at his mercy.
Wednesday were enjoying particular success down the right flank with James Tavernier, on loan from Newcastle , testing the credentials of West Ham's 17-year-old left-back Dan Potts.
Tavernier fashioned the first chance of the game when he flashed a shot across Boffin's goal and then beat Potts, son of former Hammers captain Steve, to whip in a right-wing cross which just evaded O'Grady.
But the much-changed visitors did have plenty of possession with Jack Collison providing their impetus. The Wales midfielder broke forward to create his team's best chance as Sears looped a three-yard header over Weaver's goal shortly before the break.
The Hammers, who won only one of their five league games during December, returned to form with a 1-0 win at Coventry last weekend .
However, there was a lack of cohesion from their makeshift side and they created little until Winston Reid tumbled under the challenge of Reda Johnson in the Owls box with referee Keith Stroud immediately pointing to the spot.
Baldock, who has failed to score in his last nine games, could not convert before O'Grady lashed home when alone in the Hammers box.
Wednesday defender Julian Bennett had been stretchered off after a nasty-looking collision and it meant there was 11 minutes of injury-time for West Ham to find a leveller.
But the Owls hung on as Megson won the battle of the former Bolton bosses.
Sheffield Wednesday boss Gary Megson said: "We are all pleased when we get a result and we all suffer as one when we don't.
"This is a good afternoon for us, but another game at Hillsborough when we don't lose.
"We don't think so much about the opposition, we just want to keep the run going for as long as we can."
West Ham manager Sam Allardyce added: "We did everything right apart from not finishing our chances and making a basic error that cost us the tie.
"The changes we made weren't the problem. The problem was not finishing the chances we had, the biggest one being the penalty."
Live Text Commentary
Full Time The game is over, as the referee blows his whistle.90:00 +11:11
Joey O'Brien challenges Ryan Lowe unfairly and gives away a free kick. Direct free kick taken by Ryan Lowe.90:00 +10:22
Free kick taken by Jermaine Johnson.90:00 +10:22 Booking
Booking Booking for Daniel Potts for unsporting behaviour.90:00 +10:14
Free kick awarded for an unfair challenge on Chris O'Grady by Daniel Potts.90:00 +9:19
Brian Montenegro produces a right-footed shot from inside the area that clears the crossbar.90:00 +8:27
Foul by Jose Vitor Semedo on Winston Reid, free kick awarded. Free kick taken by Ruud Boffin.90:00 +7:21
Centre by Joey O'Brien, Headed effort from deep inside the area by Sam Baldock misses to the right of the target.90:00 +5:23
The offside flag is raised against Chris O'Grady. Ruud Boffin restarts play with the free kick.89:06
Jack Collison takes the free kick.89:06 Booking
Booking Clinton Morrison is shown a yellow card.89:01
Unfair challenge on Daniel Potts by Clinton Morrison results in a free kick.87:30
The assist for the goal came from Clinton Morrison.87:30 Goal scored
Goal! - Chris O'Grady - Sheff Wed 1 - 0 West Ham Chris O'Grady finds the back of the net with a goal from just inside the area to the bottom left corner of the goal. Sheff Wed 1-0 West Ham.86:51
Free kick awarded for a foul by Chris O'Grady on Winston Reid. Ruud Boffin takes the direct free kick.86:06 Substitution
Substitution Julian Bennett leaves the field to be replaced by Ryan Lowe.79:00
Corner taken by Robert Hall played to the near post, Nicky Weaver makes a save.77:24 Substitution
Substitution Brian Montenegro comes on in place of Gary O'Neil.75:13
Corner taken by Chris Lines.75:05
Jermaine Johnson sends in a cross, Daniel Potts makes a clearance.
The ball is swung over by Clinton Morrison, Joey O'Brien manages to make a clearance.73:37
The ball is sent over by Daniel Jones, Winston Reid manages to make a clearance.72:00 Substitution
Substitution Robert Hall is brought on as a substitute for Freddie Sears.71:43 Substitution
Substitution Daniel Jones joins the action as a substitute, replacing James Tavernier.71:33
Chris Lines crosses the ball, Header on goal by Danny Batth from inside the box goes harmlessly over the target.71:04
Chris Lines takes the direct free kick.71:04 Booking
Booking George McCartney goes into the book.70:56
Foul by George McCartney on Julian Bennett, free kick awarded.70:32
Sam Baldock has a drilled shot. Nicky Weaver makes a fantastic save.69:23
Chris Lines challenges Jack Collison unfairly and gives away a free kick. Direct free kick taken by Ruud Boffin.69:13
Jermaine Johnson has a drilled shot. Joey O'Brien gets a block in.67:22
Jack Collison takes a outswinging corner to the near post, clearance by Danny Batth.66:39
Outswinging corner taken right-footed by Jack Collison, clearance by Danny Batth.66:30
Shot by Freddie Sears from 18 yards. James Tavernier gets a block in.65:26
Outswinging corner taken from the right by-line by Chris Lines, Ruud Boffin makes a comfortable save.65:04
Chris Lines has a drilled shot. George McCartney gets a block in.64:20 Substitution
Substitution (West Ham) makes a substitution, with Frank Nouble coming on for John Carew.62:36
Chris O'Grady delivers the ball.61:39
Direct free kick taken by Chris Lines.60:46
Winston Reid concedes a free kick for a foul on Chris O'Grady.60:02
Foul by Sam Baldock on Jose Vitor Semedo, free kick awarded. Direct free kick taken by Nicky Weaver.58:49 Substitution
Substitution Clinton Morrison joins the action as a substitute, replacing Reda Johnson.58:34
Henri Lansbury has shot on goal from a long way out that goes wide left.56:18
The ball is swung over by Jermaine Johnson, Ruud Boffin makes a comfortable save.55:24
Jon Otsemobor takes a shot from inside the box clearing the bar.52:54
Free kick awarded for a foul by John Carew on Danny Batth. Direct free kick taken by Jon Otsemobor.50:09
Jon Otsemobor fouled by John Carew, the ref awards a free kick. Direct free kick taken by Nicky Weaver.48:40
Inswinging corner taken by Jack Collison from the left by-line.48:34 Penalty
Penalty taken by Sam Baldock is saved by Nicky Weaver. Sheff Wed 0-0 West Ham.47:50
Reda Johnson concedes a Penalty for a foul on Winston Reid.47:29
Short corner taken by Sam Baldock.47:20
Sam Baldock produces a cross, Rob Jones gets a block in.45:01
The referee blows his whistle to start the second half.45:00 +2:11 Half time
Half Time The referee blows for half time.45:00 +0:09
Free kick awarded for a foul by Jack Collison on Jose Vitor Semedo. Nicky Weaver takes the direct free kick.44:18
Volleyed right-footed shot by Jack Collison. Save made by Nicky Weaver.44:12
The ball is crossed by Gary O'Neil, Rob Jones manages to make a clearance.43:46
Inswinging corner taken from the left by-line by Jack Collison.42:11
Outswinging corner taken from the right by-line by Chris Lines, Danny Batth takes a shot. Chris O'Grady gets a block in.42:03
A cross is delivered by James Tavernier, George McCartney manages to make a clearance.41:00
The ball is crossed by Chris Lines, George McCartney makes a clearance.39:59
Shot by Sam Baldock went wide right of the post.37:54
The ball is delivered by Jack Collison, Freddie Sears produces a header from inside the six-yard box that clears the bar.36:39
Header by Danny Batth from deep inside the penalty area misses to the left of the goal.35:12
Winston Reid fouled by Jermaine Johnson, the ref awards a free kick. Ruud Boffin restarts play with the free kick.31:21
The official flags John Carew offside. Nicky Weaver takes the free kick.30:47
Free kick awarded for an unfair challenge on Joey O'Brien by Reda Johnson. Gary O'Neil takes the direct free kick.30:03
Free kick awarded for a foul by James Tavernier on Henri Lansbury. Free kick taken by Ruud Boffin.29:15
Jack Collison challenges Jon Otsemobor unfairly and gives away a free kick. Direct free kick taken by Nicky Weaver.28:54
James Tavernier crosses the ball, save by Ruud Boffin.27:43
Corner taken by Jack Collison from the right by-line, Nicky Weaver makes a comfortable save.26:29
Centre by Joey O'Brien.26:04
The ball is crossed by Daniel Potts, Nicky Weaver makes a comfortable save.24:25
George McCartney challenges Jermaine Johnson unfairly and gives away a free kick. Free kick taken by Nicky Weaver.22:39
Chris O'Grady fouled by Henri Lansbury, the ref awards a free kick. Free kick taken by Chris Lines.22:03
The ball is swung over by Sam Baldock, save by Nicky Weaver.19:01
Shot by Jermaine Johnson from deep inside the penalty area misses to the right of the target.18:10
Free kick awarded for a foul by Rob Jones on Sam Baldock. Gary O'Neil takes the direct free kick.16:14
Free kick taken by Rob Jones.16:14 Booking
Booking Gary O'Neil is shown a yellow card for unsporting behaviour.15:53
Free kick awarded for an unfair challenge on Jose Vitor Semedo by Gary O'Neil.13:45
Jose Vitor Semedo fouled by Henri Lansbury, the ref awards a free kick. Free kick taken by Jon Otsemobor.12:24
Sam Baldock has shot on goal from just outside the box which goes wide of the right-hand upright.11:35
James Tavernier has an effort from just inside the box that misses to the left of the goal.7:04
Reda Johnson gives away a free kick for an unfair challenge on John Carew. Gary O'Neil produces a shot on goal direct from the free kick.5:36
Corner taken by Joey O'Brien, save by Nicky Weaver.5:25
Henri Lansbury delivers the ball, fantastic save by Nicky Weaver.4:38
Effort from a long way out by Jermaine Johnson goes wide right of the target.1:50
The assistant referee signals for offside against John Carew. Free kick taken by Nicky Weaver.0:00
The referee gets the match started.
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