Queens Park Rangers manager Harry Redknapp admitted Sheffield United deserved their FA Cup third-round win at Loftus Road on Sunday.
Marc McNulty gave the Blades a first-half lead against QPR and Jamal Campbell-Ryce netted twice in the second half to clinch a memorable 3-0 win.
QPR have won only two cup ties in the last 11 years, with several of their early exits coming at the hands of lower-division opposition.
Redknapp, who made seven changes but still fielded an experienced side, said: "They looked sharper than us all over the pitch.
"They were brighter and better than us and looked like a team that had 10 days without playing a game -- we were playing our fourth and looked lethargic. We looked sluggish today.
"They thoroughly deserved their win. They played well and you've got to give them the credit. Look at their record -- they got to the semifinals last year and this year are in the semifinals of the Capital One Cup.
"It's no good shouting and screaming. What can you do? Our home form has been fantastic. But we didn't play well today and the third goal summed us up. That was a horrendous goal."
Sheffield United will also face Spurs in the semifinals of the Capital One Cup having already knocked Southampton and West Ham out of the competition.
And their FA Cup third-round victory against Rangers rekindled the spirit of last season, when United beat top-flight sides Fulham and Aston Villa on the way to the semifinals.
First-team coach Chris Morgan warned Tottenham will not be able take Sheffield United lightly after the Blades pulled off yet another cup upset on Sunday.
Morgan, speaking to the media instead of manager Nigel Clough, said: "Everybody in the semifinal draw would have wanted to play us.
"The Premier League clubs would want to avoid each other, it's just the nature of the beast.
"But I don't think people will take us lightly, because of the results we've had. In the last calendar year we've beaten five Premier League clubs.
"The semifinal will be different in that it's over two legs. But with the atmosphere and the type of performance we can get at home, we know if we're still in the tie when we get back to Bramall Lane then there will be a game on.
"We had a great run last year, getting to the semifinal, and this year we've backed that up with some really good performances."
Morgan added: "We were confident but when you come away to Premier League sides you've got to work hard and get the blocks in like we did.
"We know we can come and compete with top teams. It's great to have a run in the cup -- great for supporters and for the revenue of the club."