Hull manager Nigel Pearson admitted "alarm bells are ringing" after his side crashed out of the Carling Cup at the hands of npower League Two side Macclesfield.
Emile Sinclair struck in each half to secure the Silkmen a shock first-round win in front of a crowd of 4,826, the lowest ever at the KC Stadium.
Pearson, whose side were jeered off at the final whistle, told the Hull Daily Mail: "To be beaten at this stage again by a lower league side is clearly not good enough."
He added: "It was a poor performance, it wasn't good enough. There's certainly a few alarm bells ringing, there's no doubt about that.
"We've not shown enough quality and at times not shown enough desire. That's very disappointing."
Hull, who went down 1-0 at home to Blackpool in their opening league game last Friday, were without nine first-team players against Macclesfield - three through injury, while six were on international duty.
Pearson added: "That was the best side I could have fielded and it wasn't good enough. That's very frustrating.
"I'm not making excuses. We should have still had enough to beat Macclesfield. They've had two attempts I think and scored two goals."
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