Tottenham opened their Premier League campaign with a victory at Newcastle for the second year running as goalline technology set them on their way.
Jan Vertonghen's early header put Spurs ahead, with technology confirming his effort had crossed the goalline by 9mm.
That advantage was short-lived as the hosts equalised 149 seconds later, when Joselu headed in Matt Ritchie's superb cross after being left unmarked six yards from goal.
However Tottenham, fielding several of their World Cup stars including England's Harry Kane and Dele Alli, grew stronger as the game progressed.
And as Newcastle's early energy began to wane, Alli put the visitors back in front, timing a back-post run to perfection to meet Serge Aurier's cross with a textbook header past home goalkeeper Martin Dubravka.
New signings Ki Sung-yueng, Fabian Schar, Salomon Rondon and Yoshinori Muto all started as substitutes for Rafael Benitez's team, who threatened to level for a second time after the break.
But Kenedy spurned a glorious opportunity with a poor first touch, Mohamed Diame thrashed a shot against the post and Rondon, on as a substitute, hit the crossbar with a deflected shot.
It was the second season in a row that Tottenham had won their opening fixture in the north east, with Alli scoring on both occasions.
No signings, no problem for Spurs
Despite declarations of contentment by manager Mauricio Pochettino, it is difficult to imagine that the Argentine's job will not be made more difficult this term by Spurs' inactivity in the transfer market.
Clubs at the top end of the Premier League all strengthened while Spurs became the first Premier League club to not make a summer signing since the current transfer window system was adopted in 2003.
In a summer when nine first-choice players had a virtually non-existent pre-season - after reaching the later stages of the World Cup - Pochettino was forced to field six of them against Newcastle.
France's World Cup-winning goalkeeper, Hugo Lloris, Belgium's Vertonghen and England's Alli, Kane and Eric Dier all started while Mousa Dembele was introduced midway through the second period.
With the familiarity of those players clear to see, Tottenham dominated possession with 60% of the ball.
And Pochettino is now going to be reliant on those players to secure a top-three finish for the fourth year running.
Worryingly for Tottenham, Kane's August Premier League goal drought continued into a 14th match.
In a largely anonymous display, the England captain managed just four touches in the Newcastle penalty area.
Newcastle revert to type
If it was a case of same old Spurs, Newcastle also reverted to type after an acrimonious summer in which the club was forced to defend its recruitment strategy and had been embroiled in a dispute with its players over bonuses.
Having outlaid just over £20m on players, Newcastle supporters have questioned the perceived ambition of the club.
And a large group of fans protested against Mike Ashley's ownership outside the city centre Sports Direct store before kick-off.
Rafael Benitez deployed an XI that featured nine of the players who dispatched Chelsea 3-0 on the final day of the 2017-18 campaign.
However, with four of his five new permanent signings named as substitutes, Newcastle were unable to capitalise as Tottenham tired late on.
Rondon, who inherited the club's iconic number nine shirt, was introduced with 30 minutes remaining but touched the ball just 11 times.
The Venezuelan, who registered 15 league goals over the previous two seasons, will have his work cut out to emulate the feats of former favourites Jackie Milburn, Malcolm Macdonald, Andy Cole and Alan Shearer.
Man of the match - Jan Vertonghen (Tottenham)
What they said - 'Dele has been strong and focused'
Tottenham manager Mauricio Pochettino speaking to BBC Sport: "To connect everything and start to mould the machine again was a massive challenge for everyone.
"The effort from the players was massive, it is not easy to provide them a good holiday and rest.
"I am happy in the way the players arrived after the holidays, and Dele [Alli] was one of them. He has been strong and focused and he has shown good quality today.
"It is important to be strong from the beginning and have belief and convey a positive message. The staff and the players need to stay together and the most important thing is the fans in a difficult time because we are going to move to a new stadium."
Newcastle manager Rafael Benitez speaking to BBC Sport: "I think we deserved more. The team worked hard against a very good side. We conceded and reacted well, and then went a goal behind again and showed good fight."
Asked about his team selection, Benitez added: "We had to give something to the players that have been training for one month so it was the right thing to do. Now we have more time, and everybody has to fight for their place. You cannot complain about Joselu's work rate, and he got a goal which helped the team.
"We tried to change something and then we had a chance when [Salomon] Rondon hit the crossbar, but you can see the new players will need some time to settle and understand their team-mates."
Match stats - Alli goal a good omen for Spurs
- Tottenham have won four of their past five Premier League away games against Newcastle (L1) - one more than they had won in their previous 19 trips to St James' Park in the competition (W3 D5 L11).
- Newcastle have lost five of their past six opening games to a league season, drawing the other vs Southampton in 2015-16.
- Tottenham have scored in 25 of their past 26 Premier League games against Newcastle, failing only in a 0-1 home defeat in November 2013.
- The first three shots on target in this match all came in the opening 18 minutes and were all scored, while none of the following four were converted.
- Tottenham's Dele Alli has scored in 33 different Premier League games and never ended on the losing side (W27 D6). Only James Milner (47) and Darius Vassell (46) have ever scored in more without losing.
- Tottenham defender Jan Vertonghen's goal was his first in 161 Premier League games, since netting against Swansea in March 2013.
- Tottenham's Harry Kane has never scored a Premier League goal in August, despite playing 14 games, 988 minutes and attempting 46 shots.
- Joselu also scored Newcastle's opening Premier League goal in 2017-18 - he's the first player to score the Magpies' first goal in consecutive Premier League seasons.
Newcastle go to Cardiff next Saturday (12:30 BST) while Tottenham host Fulham on Saturday (15:00 BST).