West Ham manager Sam Allardyce blamed rookie Callum McNaughton's red card for his side's 2-1 Carling Cup humiliation by Aldershot.
The Hammers were booed off after letting in a late goal for the third match running at Upton Park as Danny Hylton's strike ensured the League Two Shots reached the second round for the first time since they reformed in 1992.
It leaves Allardyce still searching for an elusive first home win as Hammers boss but he said: "We didn't get our first win because we went down to 10 men, it's as simple as that. Even if the opposition are not in the same division it gives them a massive lift."
He added: "We were nice and comfortable but unfortunately a young man on his debut gets caught out and gets sent off. By the letter of the law the referee has seen it as a goalscoring opportunity, he's last defender so he has to do what the rules tell him."
Allardyce, who says his players are scared of playing at home, made nine changes including a debut for 19-year-old centre-half McNaughton, and all looked well when Junior Stanislas fired them into the lead with a superb curler after a quarter of an hour.
But their night, and in particular McNaughton's, went sour when he was sent off for scything down Hylton a minute after half-time.
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