Goalkeeper Joe Hart described West Ham's performance as "terrible" as League One Shrewsbury Town held them to a goalless draw to force an FA Cup third-round replay.
The hosts, who are second in League One, dominated for large parts of the game but were unable to find the winner, while West Ham could only register two shots on target.
When Shrewsbury-born Hart was asked after the game if his side had got out of jail, he replied: "100%. We were terrible today and Shrewsbury were really good."
Ben Godfrey almost poked home from Shaun Whalley's free-kick in the first half, before Mat Sadler saw his chance saved by Hart.
The Hammers, who made four changes from Thursday's Premier League draw with Tottenham, looked lethargic in their third match in six days and only threatened through half-chances from Andre Ayew.
"It's a tough place to come. We didn't play well. We had three games in a week and there were opportunities for the lads, including myself," added Hart.
"I can't blame fatigue. There was some terrible football played today and we lost a lot of battles."
The result means the Shrews will now travel to London Stadium later this month for the replay, with the hope of reaching the fourth round of the competition for only the second time in 14 seasons.
West Ham, meanwhile, will be hoping to avoid being knocked out in the third round for the sixth time in eight years.
Hart goes home as West Ham struggle
Hart was recalled to the first team and made captain for his return to his boyhood town and the club where he started his career.
He got a warm reception as he walked out on to the pitch at Montgomery Waters Meadow and said after the game: "This is where I grew up, my home town. It gave me my opportunity in football. It's very special."
The England international made strong saves to deny Godfrey and Sadler from close range, while West Ham's defence was able to scupper a late attack from captain Abu Ogogo in stoppage time.
Shrewsbury, two points off leaders Wigan in the third tier, boast an enviable defensive record with only four goals conceded at home this season.
But, in truth, West Ham offered little to trouble their back line.
The visitors had only four touches in the opposition's penalty area and their only chances came from Ayew - his low, tame effort in the first half coming before a flicked header after the break.
A toothless display
Mat Sadler and Josh Cullen needed treatment for nasty injuries during the game
It was a memorable, if painful, domestic debut for 21-year-old West Ham midfielder Josh Cullen, who lost his front tooth after receiving a high boot to the face from Ogogo.
Cullen's tooth was retrieved from the pitch by the Hammers physio and the Republic of Ireland U21 international was able to continue playing - but only after being made to change his shorts on the side of the pitch as they were covered in blood.
Shrewsbury defender Sadler also needed extensive treatment after a clash of heads with Ayew. The 32-year-old needed two trips off the field to deal with the bleeding and ended up with a bandage around his head for the second half.
'Mixed feelings' for Shrewsbury - what they said
Shrewsbury Town manager Paul Hurst: "The players are a little bit deflated almost.
"To their credit, they did extremely well but if we'd had just that little bit of quality and we may have got through. So it's mixed feelings really.
"But we have a replay to look forward to. We know it will be tough. They will be at home, more comfortable in their own stadium."
West Ham manager David Moyes: "I don't think we showed any quality and the biggest disappointment is I didn't think we showed enough steel.
"When you come to places like this you have to show yourself physically, that you can battle and compete. I didn't think we did that at all and that was the worst thing about it.
"Obviously if you compare Wembley and Thursday night, it's a big change. But it's a mentality thing. You've got to go and show that wherever you are, you've got to respect whatever players you're against and recognise it's going to be tough."
