Paulinho's stoppage-time winner for Tottenham settled a tense encounter against Cardiff to move Spurs into second place in the Premier League.
Bluebirds goalkeeper David Marshall produced a series of outstanding saves to keep the Londoners at bay.
But the Brazilian back-heeled in Erik Lamela's low cross right at the death.
Cardiff 0-1 Tottenham: Villas-Boas says late winner was justified
It was nothing more than Andre Villas-Boas' side deserved after dominating for long periods against Malky Mackay's dogged side.
Gylfi Sigurdsson was the first Spurs man to be denied by Scotland's Marshall, though at the other end Frenchman Hugo Lloris had to be alert when Fraizer Campbell was given the chance to open the scoring.
Home fans were convinced Lloris had handled the ball outside the area as he took it from Campbell's feet.
A goal for the hosts would have been against the run of play, however, a fact underlined when Andros Townsend's run and cut-back gave Roberto Soldado a chance.
Former Spurs defender Steven Caulker then had to block another Soldado effort, an intervention that indirectly produced the best save of the opening period.
Spurs' swift start
Tottenham have now won four of their first five Premier League encounters for the first time since 2009-10. And of 15 top-flight games against Cardiff, Spurs have won eight, drawn three and lost four.
Sigurdsson was first to the rebound, whipping in a low shot that seemed net-bound. But Marshall's instinctive dive and fingertip touch ensured the ball trickled harmlessly behind.
Having hardly been troubled in the Spurs goal, Lloris then gifted Cardiff a corner when he failed to control a long ball with his feet.
From the corner, Lloris was beaten by Ben Turner's header but the goal was ruled out for Aron Gunnarsson's goal-line tug on the keeper.
The hosts also had the first chance after the break as Craig Bellamy went clear on the right only for Lloris to intercept a cross intended for Peter Whittingham.
But the focus was back at the other end when Sigurdsson's drive - a strike so powerful it turned out to have burst the ball - came back off the cross-bar and Soldado's first-time follow-up produced a two-footed block from Marshall.
Cardiff 0-1 Tottenham: Malky Mackay - Hugo Lloris is a lucky man
Cardiff boss Mackay sent on former West Brom striker Peter Odemwingie for his debut as the hosts sought a winner.
The Nigeria international's introduction gave the hosts fresh impetus and everyone in the ground thought he had created the opener with a pull-back for Gunnarsson that the unmarked midfielder could only turn high over the bar.
Marshall continued his outstanding display to close down Kyle Naughton and again deny Soldado before Paulinho's cute finish finally broke Cardiff's resistance.
Cardiff City manager Malky Mackay:
"The boys put in a magnificent effort against a very good team. The amount of chances we had, the disallowed goal. Hugo Lloris is a very lucky man tonight. It's about being more clinical but we matched a very good team toe to toe again.
"We put them under pressure and I'm very proud of my players. They're a great group to work with and I'm glad I'm in the trenches with them this season.
"They're relishing the size of the task this season and are giving as good as they get. They're loving the fact that we're in the Premier League and we're actually competing."
Tottenham manager Andre Villas-Boas:
"Today it was different from normal in that there was justice in football. We created so many chances that there could only be one winner.
"Last season we had the best record away from home after Man United. We looked very strong. Bearing in mind the win they got against Man City there won't be many teams getting points here so I'm happy.
"[Cardiff's] David Marshall is a great goalkeeper. He did extremely well today. It's a great win. But I suffered a lot…like everyone else!"
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