West Ham boss Sam Allardyce was left to rue yet another home draw as Middlesbrough substitute Bart Ogbeche stole a share of the spoils at Upton Park.
Abdoulaye Faye's deflected goal off Joe Bennett midway through the second half looked to have reignited the hosts' Championship promotion bid.
But the Hammers have not won a league match on a Tuesday night in front of their own fans in more than two years, and Nigerian forward Ogbeche's superb strike ensured that sorry run continued.
The final whistle was greeted by a chorus of boos and Allardyce admits his players are feeling anxious every time they play on their own turf.
He said: "Eventually these draws will cost us. We were very, very patient tonight and got into the lead which was not easy because of the way the opposition sets up against us.
"It's frustrating because this is the best unbeaten run we've been on this season but we're not getting the points that we need from these matches.
"We didn't have that little bit of quality or the ability to just add the killer instinct and then we go and concede one of the best goals this season, it was a real moment of quality.
"It is five draws at home but then one of those was against Southampton when we had 10 men for most of the game.
"The turning point for me is the save that their goalkeeper made from James Tomkins when we were 1-0 up. If we had got it to 2-0 I think that would have been game over."
Reading's shock defeat at Peterborough leaves West Ham just two points adrift of the Royals in third place while Boro are now up to fifth place.
"It's a bit crazy that it's all doom and gloom and here we are, both clubs in the top six," said Boro boss Tony Mowbray.
"I was pleased with the way that we came here and set up to frustrate West Ham because of the run they've been on we thought we could play on their anxiety a bit.
"We're in the top six and with a bit of luck and a few players back hopefully we will stay there in the last nine games of the season and get into the play-offs.
"I'm pleased for Bart - he does that kind of thing every day in training but he's been coming into my office this week and asking me for more game time.
"Had he not done that would he have got his chance today? It's very hard to say but I'm pleased that he did."