Harry Kane's second half header ultimately proved the difference but the margin of Tottenham's supremacy was hardly reflected in the narrow 1-0 scoreline.
Although Tottenham's Wembley form has improved this term, the Gunners won the reverse fixture 2-0 and have been boosted by the recent acquisitions of Pierre-Emerick Aubameyang and Henrikh Mkhitaryan.
Kane headed home the victor early in the second half at Wembley, and leads the Premier League scoring charts with 23 goals to his name already, or 32 from 33 appearances in all competitions.
"It's a game we couldn't afford to lose, of course", the Frenchman said.
He added: "Football is about trust, belief and confidence". Because about his quality, there is no doubt ... for me he is a genius, and unbelievable player. "If he can train, he can give you this type of performance".
Arsenal could be without Petr Cech for the match.
As the half drifted on, Spurs began to get the upper hand but were let down by a lack of composure.
Harry Kane scored the only goal of the game as Spurs moved seven points ahead of Arsenal
Harry Kane rises to head home.
Petr Cech spared his teammate's blushes, and the Arsenal's first sight of goal arrived shortly afterwards when Hector Bellerin's cross was deflected into the path of Jack Wilshere, but the England global completely missed the ball with his right-footed effort.
Four minutes in, Kane kept up his remarkable record against Arsenal.
He made a couple of marvellous saves to help Arsenal remain fighting in the game.
For Spurs' goal, Ozil again done his job by pressing Dembele on the ball, but the fact Xhaka was out of position allowed his pass to find Ben Davies unmarked, with the Welshman then delivering a ideal cross for Kane to nod home.
Not only because it was a north London derby and obviously this is the most important game for Arsenal fans.
Kane then headed Christian Eriksen's precise cross over while at the other end, Hector Bellerin shot wide after being put clear by Mesut Ozil.
It set a pattern. The 30-year-old has been one of the stalwarts of the Spurs defence in recent years alongside Toby Alderweireld, with the Belgian also returning to contention after a long-term injury.