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Northampton manager Keith Curle, speaking to BBC Sport: "We all needed to be on the same page today. Today showed the work in progress and the work we put in at the football club.
"You’ve got to give Derby credit - they showed good application in an unfamiliar setting and rose to the challenge that was set to them.
"We’ve earned the draw over 94, 95 minutes. The replay gives us another opportunity to go to Derby and put in another performance that we’re proud of.
"We might be able to express ourselves a little more on the ball at their place."
On Charlie Goode's foul on Jack Marriott: "I did see it. The referee was unsighted. A red card would have changed the flow of the game massively, but we showed that we can compete against a very good football club."
QPR boss Mark Warburton: "I feel like we have gone out without having a real crack at it tonight. It was a poor goal.
"We had a couple of big chances that we have to score. To score at the death is almost irrelevant the damage was done earlier.
"It was a cheap sloppy goal to give away, track your runners. We got into good areas but never felt threatening in the first half. If you give away a cheap goal you pay the price."
Excellent work from Northampton boss Keith Curle, who says in his post-match interview he couldn't see the incident before moments later admitting he actually could.
Derby manager Phillip Cocu continued his frustration into his BBC Sport interview: "I think it’s a foul. If he doesn’t pull Jack Marriott down, he'd be one on one and probably score.
"There's only one decison to make. I cannot imagine why he doesn’t give it. He tried to be man of the match and he became man of the match.
"Northampton deserved credit. They played a good game. They had passionate home fans, it was a great atmosphere. They played a direct style of football.
"In some periods we struggled to keep the ball down and play our game. In some periods we did well, especially on the right side. You have to score. It was a real cup game. I enjoyed it – except for the important decision.
"We knew what was going to happen – two strong strikers and a lot of support for second balls. Second half we improved and had more control. It’s a pity we couldn’t score the goal we needed."
Derby boss Phillip Cocu, speaking to BT Sport: "It is the only key moment in the game [the potential red card for Charlie Goode]. If this is not a red I don't know what is. If he doesn't pull him down it is a goal. The fourth official said it was also a foul. But the referee decided it was not a foul.
"We knew it would take 15 minutes or more to get some space because of the way they play. We knew it would not be easy to play combination kind of football. After that we got better control and moved the ball around so they had to open up.We had good moments but couldn't score a goal. We have to play again.
"The way Northampton play their game, they did well and are passionate. The fans gave them a lot of support and they played a good game. A good result for them but with 10 v 11 it would be a different game. And now we have a home game to try to win the tie."
This was QPR's late consolation.
Northampton captain Charlie Goode admits he feared being sent off in the first half. The defender appeared to haul down Jack Marriott, who was through on goal.
He would have been facing a red card for a professional foul, but referee Darren England thought it was not a foul.
"Their striker was fuming," Goode, who went on to be named man of the match, told BT Sport.
"I won't lie and say I wasn't worried. It was a tangle of legs. Luck was on our side."
Sheffield Wednesday boss Garry Monk: "It was a tough game again but it was a good performance from ourselves. There was a bit of drama at the end but I'm very pleased to get in to the fifth round.
"We had a hugely disappointing result in the last game [a 5-0 home defeat by Blackburn] and with 3,000 fans travelling here we wanted to restore a bit of pride into that shirt.
"Our challenge and ambition today was to show pride, no matter what the result was. We had to repay the fans and make amends."
Here was Sheffield Wednesday's late second. It looked like the clincher, although it wasn't the last goal in the game.
One shot on target in the whole match - to Northampton. The Cobblers had 10 shots off target and another three blocked. Derby had nine shots in total.
Former Charlton player on BBC Radio 5 Live Sports Extra
It was a good performance from Sheffield Wednesday.
They absorbed all of QPR's pressure, hit them on the break and took their chances.
- SMS Message: Hi. Sorry I only just woke up. Has there been any football at all played in the Derby game I would hate to have missed it. from Big Pete
The fifth-round draw will be shown live on The One Show on Monday and will take place just before 19:20 GMT.
It's all over. Sheffield Wednesday are in the FA Cup fifth round.
Goalkeeper Joe Lumley almost gets onto it but can't get a shot away.
QPR have a corner. And the KEEPER IS UP!!!
A late flurry of goals.
Nahki Wells goes round the keeper to slot home. QPR couldn't, could they?
It's all over and Northampton will face a replay at Pride Park.
It should be said this was a terrible game from a neutral point of view.