Unai Emery's first north London derby will certainly not be one he forgets in a hurry.
In one of the games of the Premier League season, Arsenal came from 2-1 down to beat bitter rivals Tottenham 4-2 at the Emirates.
Pierre-Emerick Aubameyang helped himself to a brace, Alexandre Lacazette scored the crucial third goal and Lucas Torreira capped off a wonderful performance late in the second-half.
Spurs' Jan Vertonghen was also given his marching orders for picking up two yellow cards.
The Gunners have now leapfrogged Mauricio Pochettino's side in the table, with a tough trip away at Manchester United awaiting them on Wednesday.
A number of Arsenal players turned in brilliant displays, but it was summer signing Torreira who really caught the eye once again.
The £26m arrival already looks like the signing of the season, dominating Spurs' midfield throughout.
Eric Dier, Moussa Sissoko, Dele Alli and Christian Eriksen simply couldn't get near the diminutive Uruguayan.
And there was one clip from the first-half that perfectly summed up what Torreira has brought to this Arsenal side.
His tenacity to win the ball off both Alli and Eriksen in the corner in a matter of seconds is just brilliant to watch.
Arsenal have missed a player like that ever since Gilberto Silva departed the club.
Torreira arrived at the club from Sampdoria with a glowing reputation from his days in Italy and starred for Uruguay at the World Cup.
However, no one expected the 22-year-old to settle into Premier League life quite as easy as this.
Torreira has improved all those around him, with Granit Xhaka in particular benefitting from his presence in midfield.
In the space of a few months, the Uruguayan has gone from new arrival to arguably the most important player at the club - money well spent.