Mistakes in both boxes cost Middlesbrough the game as the shot-shy Teessiders hit the self-destruct button at Watford.
And until they can eliminate the errors, Boro will continue to fall short, admitted angry boss Aitor Karanka.
Boro were controlling the game but struggling to score until a second-half meltdown saw them concede a sloppy penalty.
Then, having been handed a man advantage shortly after when Watford’s Samba Diakite was shown a red card for a two-footed challenge on Dean Whitehead, they threw that away within five minutes as Ben Gibson was sent off.
Young defender Gibson, who had also conceded the penalty with an ill-timed tackle, picked up a second yellow for obstructing the keeper as a corner was cleared.
The Spanish Boro boss said his players needed to be more intelligent in commanding positions and must cut out the mistakes.
“I’m very disappointed because it was a game we had to win and we had it under control,” said Karanka. “After that I don’t know what happened. We lost the game, we lost a player, we lost our identity, we lost a lot of things. Some players maybe think they’re better than they are. This game was a mixture of defending and attacking mistakes and when you do that it’s impossible to win a game.”
“The penalty was clear. It was a mistake. But I thought when they had a man sent off that we could still win the game,” added Karanka.
“But five minutes after there was another mistake and we had a man sent off. When you have one yellow card, you can’t do this. You need to be more intelligent and we lost the game for our mistakes.
“With ten against ten we couldn’t score any goals. I am told that we had most of the possession and most of the chances but it doesn’t matter as we didn’t make that count. Possession doesn’t win games, goals do.”
Boro took control early on and went close on 13 minutes as Emmanuel Ledesma latched onto a quick throw-in on the right to curl just wide, then soon after Adomah cut in from the left to drill a low shot that was smothered at the far post by the keeper.
Adomah then wriggled past his man and found Danny Graham in the box but he chipped over on the turn. And Boro thought they had scored on 37 minutes when Jonathan Woodgate headed in from a Grant Leadbitter free-kick – but the offside flag went up for a marginal decision.
However, the game turned on 50 minutes when Watford’s Forestieri cut past Gibson inside the box and was brought down by a stretching late tackle; after the referee pointed to the spot, Troy Deeney slammed home.
Boro were given a boost on 52 minutes as Diakite was sent off for a nasty tackle on Whitehead but within five minutes Gibson followed him and the game entered a stalemate.
They continued to press at Graham turned a shot into the side netting and both Mustapha Carayol and Adomah had efforts charged down, but there was no way through a massed Watford defence.
It was Boro’s fifth successive game without scoring and their goal drought now extends to eight and three-quarter hours.
Karanka confessed much of that was down to his toothless team’s on-going failings in the box.
“Sometimes it can be luck but sometimes it’s because you didn’t do enough to score goals,” he said.
“In some games, like the game at home to Blackburn we created a lot of chances and were maybe unlucky.
“But at Watford and other games, like Doncaster, we didn’t do the good things. We lost because of mistakes.”