Martin Odegaard's deflected effort on the stroke of halftime deservedly levelled things up for Arsenal and Alexandre Lacazette's 64th-minute penalty sealed their first win in six attempts against their bitter rivals.
It was a mixed afternoon for Lamela who produced an audacious 'Rabona' shot to put Spurs in front against the run of play after 33 minutes at The Emirates -- one of the most remarkable goals ever seen in the long-running rivalry.
But the Argentine, who had come on to replace the injured Son Heung-min early on, went from hero to zero when he was sent off in the 76th for catching Kieran Tierney with his forearm.
While Lamela's goal was unforgettable it could not disguise a largely disappointing display by the visitors who squandered a great chance to boost their hopes of a top-four finish.
After Lamela's sending off Tottenham's 10 men finally applied some pressure and had a Harry Kane effort ruled out late on for offside before he hit the post with a free kick.
Spurs are still without a league win at Arsenal since 2010 and the defeat left them in seventh spot, six points behind fourth-placed Chelsea. Arsenal stayed in 10th spot with 41 points, four behind Tottenham.
Photo Just Arsenal