Mauricio Pochettino left Wearside a disappointed man after seeing Tottenham pass up the chance to close the gap on Premier League leaders Chelsea.
Spurs could only draw 0-0 at bottom-of-the-table Sunderland as the Blues matched them with a 1-1 draw at Liverpool to maintain their nine-point advantage at the top of the table.
There was some consolation for Pochettino as his side at least leapfrogged north London rivals Arsenal into second place following their shock home defeat by Watford.
Asked if he was frustrated, the Argentinian said: "Not frustrated, disappointed. It was a massive opportunity to reduce the gap to Chelsea and be in second position which was important for us.
"When you drop two points like tonight, it's difficult to change the feeling. We feel bad, that's the reality.
"In the first half, we didn't play well -- we were poor. We shot once, and it's difficult to win a game in that way. In the second half, we were much better. We created some chances to score, but it wasn't enough.
"We dropped two points. We feel disappointed, but not only with the result, with our performance. We only competed for 45 minutes in the second half."
Pochettino, whose medical staff will assess the knee injury full-back Danny Rose suffered before the break, was conciliatory over a wild challenge by Black Cats midfielder Jack Rodwell on Mousa Dembele which incensed his players.
The manager said: "There is nothing to say, nothing to complain about. That is football. For the referee, it is difficult to take a quick decision. I think we need to support the decision of the referee and it's important."
Sunderland boss David Moyes was significantly happier despite the knowledge that a good point had left his side further adrift of safety as a result of Swansea's win over Southampton.
Moyes said: "It has to be a start. Look, I know how the other results have gone, so I am well aware of that. A point against Tottenham is not a bad result, and we had a point against Liverpool here a few weeks ago.
"Our home form, with the exception of probably Stoke in the Premier League, has been relatively okay for a few months. We have got a lot of big games coming at home - one point won't be enough, three points is what we are going to need to get.
"Tonight it was a tight decision whether we opened up to try to force the three or whether we tried to contain the one. Obviously Tottenham dominated the second half and we found it hard to get much going at all."
Moyes sent his players out knowing that the club's final deadline-day bid to sign Leicester striker Leonardo Ulloa following the loss of Victor Anichebe to a knee injury had failed, meaning the arrival of former Everton duo Bryan Oviedo and Darron Gibson were the last of the January transfer window.
He said: "We were trying to add to the squad if we could. We knew it was going to be a difficult few days trying to get what we wanted.
"The injury to Victor Anichebe was the thing that really made things a lot harder for us and made us have to look at things differently.
"But it wasn't for the want of trying. Some players we couldn't get and some clubs chose not to sell us their players, so because of that, that's where we are at."