Middlesbrough substitute Bart Ogbeche inflicted yet more midweek misery on West Ham at Upton Park.
Abdoulaye Faye’s deflected goal midway through the second half looked to have reignited the Hammers’ 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.
It could have been worse for the under-fire hosts but Lukas Jutkiewicz hit the bar and Ogbeche had a shot cleared off the line at the finish.
Hammers manager Sam Allardyce admits his players feel anxious every time they play on their own turf, having been booed off following three straight draws.
That was certainly apparent in a tense first half against a Middlesbrough side hardly bursting with confidence themselves on the back of successive defeats.
The Hammers went on the attack in the second half and the slice of luck they needed finally arrived in the 67th minute, courtesy of Faye.
The defender rose to meet a long, high ball from McCartney and his header spun off the back of marker Joe Bennett’s head and looped over Steele.
Tomkins could have killed off Boro with a close-range header only to see Steele pull off a stunning save. Ogbeche drew Boro level seven minutes from time, skipping past Danny Collins on the edge of the area and crashing a stunning shot past Rob Green.
West Ham United: Green, O’Brien, Faye, Collins, McCartney, Noble (Baldock 87),Tomkins, Nolan, Cole (Carew 71), Maynard (Collison 71), Taylor. Unused substitutes: Lansbury,Morrison.
Middlesbrough: Steele, Hoyte, Bates, Hines, Bennett, Thomson (Ogbeche 80), Smallwood (Martin 80), Bailey, Emnes (Zemmama 76),Jutkiewicz, Hammill. Unused substitutes: Arca, McMahon.
Referee: S Mathieson (Cheshire).