Sunderland - Tottenham manager Mauricio Pochettino admitted he was disappointed after his side dropped two points in their bid to eat into Premier League leaders Chelsea's lead with a 0-0 draw with struggling Sunderland on Tuesday.
Spurs leapfrogged London rivals Arsenal on goal-difference, nine points behind Chelsea - who were held 1-1 by Liverpool on Tuesday - after a bruising stalemate at struggling Sunderland.
Pochettino's side are unbeaten in the league since mid-December, an eight-match run that has seen them take 20 of a possible 24 points to maintain their hopes of securing at the very least a top four finish in May.
The Argentinian confessed to leaving Sunderland reflecting on what might have been at an opportunity lost.
"I'm disappointed, not frustrated," he said.
"We're on a good run at the moment, and it was a chance to cut the gap on Chelsea so when you drop two points like tonight then it's difficult not to feel bad about it."
Danny Rose faces a scan on a knee injury that forced the England defender off before half-time in an uncompromising contest.
Sunderland midfielder Jack Rodwell was fortunate to escape with only a yellow card after a sickening challenge on Tottenham's Belgian midfielder Mousa Dembele.
Spurs return to action at the weekend when they host Middlesbrough on February 4.
"Danny will be assessed," said Pochettino.
"He's twisted his knee and we'll know more tomorrow. I don't know if it was a red card for Rodwell, it's difficult for referees to take a quick decision, and we need to support his decision.
"I thought we were poor in the first half and although we were better in the second, it wasn't enough to win the game.
"We weren't aggressive enough - that was the problem and we can't afford that.
"We all need to learn and try to fix it."
Relegation-threatened Sunderland failed with late transfer bids for Leicester City forward Leo Ulloa and Southampton striker Jay Rodriguez as David Moyes attempted unsuccessfully to fill the void left by the two-month injury absence of Nigerian international Victor Anichebe.
"I don't know if I'd use the word frustrating," said Moyes, who bought in Darron Gibson and Bryan Oviedo on Monday from one of his former clubs Everton.
"We were trying to add to the squad but we knew it was going to be a difficult few days.
"The injury to Victor made the situation a lot harder for us. Some players we couldn't get, and some clubs chose not to sell their players, so that's where we're at."
The Black Cats are without a win in eight games in all competitions, but were boosted by a welcome point to lift them off the bottom of the Premier League on goal difference ahead of Hull, who play Manchester United on Wednesday.
Despite moving off the foot of the table, victory for Swansea leaves them five points adrift of safety.
"We're aware of the way the other results went, but we can't do a lot about that," said Moyes.
"What we can do is to build on what we've got, get that team spirit and toughness about us and take pride in this performance because I thought we really stuck at it."