It was easy to wonder where Tottenham Hotspur's goal was coming from, particularly when Emmanuel Adebayor limped off injured and André Villas-Boas looked at his substitutes' bench and saw no strikers. Tottenham, determined to advance their top-four credentials, had been the better and more creative team, even if Swansea City had emerged with credit for their all-round polish albeit that the decisive moment had eluded them. The home side appeared to be running out of ideas.

Enter Jan Vertonghen, the summer signing from Ajax, who has emerged as a key figure and fans' favourite. The Belgium defender built a reputation in Holland for his threat at offensive set pieces and he pressed hard on what has come to feel like Swansea's achilles heel when he scored his first goal in the Premier League and only his second for the club, after September's at Carlisle in the Capital One Cup.

The execution was as eye-catching as the timing. Kyle Walker's free-kick flicked off a Swansea head but it would be remiss to say that the ball fell kindly for Vertonghen as the visitors' defensive concentration suffered a rare lapse. Vertonghen's technique and body shape had to be perfect to convert the chance on the half-volley, with his weaker right-foot, but they were. Tottenham had the reward that they deserved.

"It was a beautiful finish," Villas-Boas said. "We knew that Swansea were among the teams who concede more from set plays so we had the chance to break the lock in those situations. It was important for Jan because he has been looking for this goal for quite some time."

The five minutes of injury time were tough for the Tottenham manager, given his team's propensity to concede vital late goals. He had no complaints about the length of time added, after six second-half substitutions and Adebayor's injury. The striker suffered a heavy ankle knock in a challenge with Leon Britton and later felt his hamstring tighten; he will undergo a scan to assess the extent of the damage. But Tottenham, to the relief of the home crowd, got the job done.

"We have addressed the [late goals] issue in training," Villas-Boas said. "We have increased the complexity of the tasks the players have been doing at the end of the sessions. The more complex the exercise, the more concentration they need at the end. It does not mean the problem is solved but the players are conscious we have conceded in the past and they want to get it right."

Swansea had never won at White Hart Lane in the league and they came to pass. And pass. In this Premier League of blood and thunder, it is remarkable to witness their patience on the ball, particularly at the back. After six minutes, the travelling support shouted "Olé, Olé" as their team revelled in possession. It was rather early for that sort of thing but it captured the essence of what has been built at the club.

But this was not a vintage afternoon for Michael Laudrup's team. Tottenham pressed them from their stride, hustled them into errors and the game might have been over at the interval after what Laudrup said had become a "very bad first half" for his side.

Tottenham created a fistful of first-half chances and none was better than that which Mousa Dembélé presented to Jermain Defoe after robbing Michu. The Swansea striker, though, tracked back to block. Adebayor drew a saving block from Chico Flores; Aaron Lennon passed instead of shooting; and Walker's vicious drive, clocked at an indecent 87mph, ricocheted clear off Gerhard Tremmel's shoulder. From the follow-up, Adebayor found William Gallas but the captain's header was weak.

Swansea found their wingers pressed back and Michu was somewhat isolated. He was reduced to trying his luck from 50 yards in the first half, and he was not far off. The visitors flickered on the counter and, early in the second half, Nathan Dyer ought to have done better with a header from Wayne Routledge's cross.

Tottenham had the majority of the second-half chances but Laudrup felt they had become "not that dangerous", which intensified his disappointment over the concession. Defoe would have made the closing stages more comfortable for Tottenham had he beaten Tremmel one-on-one in the 86th minute but Villas-Boas would savour the "patience and persistence" of his team.

There was the feel-good plus of Scott Parker's injury-time introduction for his first football of the season but Tottenham's real happiness came from a glance at the league table.

Man of the match Mousa Dembélé (Tottenham Hotspur)