Taking advantage of an abject display by Burnley, Reading, having dramatically accounted for Liverpool in the third round, deservedly claimed their second Premier League scalp.
The Championship club began poorly themselves but a much improved second-half display brought reward when Gylfi Sigurdsson, who had scored that ice-cool injury-time penalty equaliser at Anfield, steered an 87th shot past Brian Jensen.
It was only Reading's third home win of a deeply frustrating season. It was also, bizarrely, caretaker manager Brian McDermott's second win in eight matches since replacing Brendan Rodgers, both of them against top flight opponents. "I thought we looked strong and deserved it," said McDermott. "We wanted to win it, we made the substitutions with that in mind. It was important for the club finances to get into the next round. We are trying to make something of the season."
McDermott will speak to John Madejski, the Reading owner-chairman, next week and may be given the job permanently. The betting is he will have to wait, before being confirmed as caretaker to the end of the season next month. Cup wins attract the headlines, but with Reading precariously placed in the Championship's relegation zone, League victories are more important and Madejski is likely to want to see McDermott achieve some before making a firm decision.
"The results will come," insisted McDermott. He has the authority to make signings and one of them, loanee Andy Griffin from Stoke, brought immediate dividends. Not only did Griffin bring his experience to bear in defence, he played the defence-splitting pass from which Sigurdsson scored.
Burnley's visit brought unhappy memories to the Madejski. Their play-off second-leg victory here last May prompted Steve Coppell's resignation. But there was little sign of the visitors drawing confidence from that memory. Brian Laws, taking charge of his second match, was hamstrung by injuries, sickness and ineligibility in selecting a team but he admitted it still should have performed better. "We didn't control the ball well enough, and we didn't pass it well enough. In the end their pressure on the goal broke through us."
After a dire first half, Reading re-appeared as if energised by the knowledge that they had nothing to fear. Simon Church soon brought a sharp save from Jensen and though Matthew Mills headed over from the corner Reading were up and running. They might have had a penalty when the jinking Jobi McAnuff went down around the hour-mark but should have scored anyway soon after only for Sigurdsson to head wide from Ryan Bertrand's cross.
Burnley briefly rallied and Adam Federici had to make a decent save from Kevin McDonald's shot, then a superb one from David Edgar's header. Martin Paterson, who scored an excellent goal in the play-off here, blasted the rebound over from two yards.
Reading pushed on anew, lifted by Jimmy Kebe's arrival. Jensen denied Mills and Shane Long but was beaten when Sigurdsson ran across McDonald to expertly turn in Griffin's pass. "It was a top-drawer finish. He's been here since he was 12," said McDermott of the 20-year-old. "We've been waiting for him to grow."
Referee: Andy D'Urso
Man of the match: Griffin